Exhibit 4.15

                                                                 EXECUTION COPY

                                 CONFIRMATION

Date:           December 13, 2002

To:             Empresas Tolteca de Mexico, S.A. de C.V. (Counterparty)

Telecopy No.:   (528) 328 7162

Attention:      Rodrigo Trevino

From:           ING Bank, N.V. (Bank)

Telecopy No.:   +525 259 2701

Transaction Reference Number:  FC7114-Emptolmex

The purpose of this communication is to set forth the terms and conditions of
the above-referenced transaction entered into on the Trade Date specified
below (the Transaction) between you and us. This communication constitutes a
"Confirmation" as referred to in the Agreement specified below.

1.    Master Agreement

      This Confirmation supplements, forms a part of, and is subject to, the
      ISDA Master Agreement dated as of December 13, 1999 (as amended and
      supplemented from time to time, the Agreement), between you and us. All
      provisions contained in the Agreement shall govern this Confirmation
      except as expressly modified below.

2.    Incorporation of Terms

      Except as expressly set forth herein and except as the context otherwise
      requires, the terms of the Transaction (the First Transaction) described
      in the Confirmation dated December 13, 1999 (the First Confirmation)
      between Counterparty and Bank, as modified and supplemented and in
      effect immediately prior to the date hereof and immediately prior to the
      execution of Amendment No. 2 hereto, are hereby incorporated by
      reference, notwithstanding the fact that the First Transaction shall be
      terminated on or prior to the date hereof. In the event of any conflict
      between the terms of the First Confirmation and this Confirmation, this
      Confirmation shall prevail.

3.    Certain Terms

      The terms of the particular Transaction to which this Confirmation
      relates are as follows:

      Trade Date:              December 11, 2002

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      Effective Date:          December 13,  2002, which shall be the effective
                               date under each of the Group Confirmations

      Termination Date:        December 12, 2003

      Notional Amount:         USD154,625,513.40

      Forward
      Payment Amount:          USD159,080,246.91   (subject   to   the   "Early
                               Termination by Counterparty" provision below).

      The paragraphs across from the captions "Cemex ADS Purchase Procedures"
      and "Valenciana Shares Purchase Procedures" in Paragraph 3 of the First
      Confirmation shall not apply except for purposes of providing
      definitions for terms used but not defined elsewhere in the First
      Confirmation.

4.    Additional Payments by Counterparty:

(a)   On the Effective Date, Counterparty shall pay to Bank USD70,936,238.67
      as a partial prepayment of the Forward Payment Amount (the amount of
      such payment, the Initial Forward Payment Amount).

(b)   On June 13, 2003 (the Intermediate Forward Payment Date), Counterparty
      shall make an Intermediate Forward Payment to Bank of the Intermediate
      Forward Payment Amount payable on the Intermediate Forward Payment Date.

5.    Conditions Precedent

      The obligations of the parties under this  Confirmation  shall be subject
      to the conditions precedent that

       (i) each "Participant" identified in the Calculation Agency and
           Interbank Agreement shall have executed and delivered a
           Confirmation (as described therein); and

      (ii) Bank shall have received:

           (A) an opinion of Ritch, Heather y Mueller, S.C., as special Mexican
               counsel to Bank, in form and substance satisfactory to Bank,
               with respect to the matters addressed in the opinion delivered
               by such counsel in connection with the First Transaction; and

           (B) an opinion of Freshfields Bruckhaus Deringer LLP, as special
               U.S. counsel to Bank, in form and substance satisfactory to
               Bank, with

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              respect to the matters addressed in the opinion
              delivered by such counsel in connection with the First
              Transaction.

6. Representations and Agreements Annex:

      The Representations and Agreements Annex attached as Exhibit II to the
      First Confirmation is hereby incorporated into this Confirmation as if
      set forth in full herein, and the representations contained therein are
      representations for purposes of Section 3(d) of the Agreement.

7.    Definitions

      For purposes of this Confirmation, the following terms shall have the
      following meanings:

      Adjusted Forward Payment Amount means the USD amount as determined by
      the Calculation Agent according to the following formula:

           PV of (a - b - c - d)

           where

           a = Forward Payment Amount
           b = USD72,979,899.07 (FV1 of the Initial Forward Payment Amount)
           c = The FV2 of the Intermediate Forward Payment Amount
           d = Aggregate of all FV2 of the Advanced Forward Payment Amount

      provided that, on and after the Termination Date, the "Adjusted Forward
      Payment Amount" will be the amount determined by the Calculation Agent
      to be equal to (a) the Forward Payment Amount less (b) USD72,979,899.07
      less (c) the FV2 of the Intermediate Forward Payment Amount less (d) the
      Aggregate of all FV2 of the Advanced Forward Payment Amount

      Calculation Agency and Interbank Agreement means the Calculation Agency
      and Interbank Agreement dated as of December 13, 1999 between Empresas
      Tolteca de Mexico, S.A. de C.V., the Calculation Agent, and each of the
      banks or other financial institutions party thereto, as amended on
      December 13, 2002 and as further modified and supplemented and in effect
      from time to time.

      FV2 means, with respect to any Advanced Forward Payment Amount or
      Intermediate Forward Payment Amount, the value on the Termination Date
      that, when discounted to the date of payment of such amount (on a 30/360
      basis compounded quarterly) at the Swap Rate, equals such Advanced
      Forward Payment Amount or such Intermediate Forward Payment Amount, as
      the case may be. As used in this definition, Swap Rate means, as of any
      date of payment referred to above, the fixed rate of interest (computed
      on a 30/360 basis) equivalent, for the period from and including the
      date of payment of such amount to but excluding the Termination Date, to
      three-month USD-LIBOR-BBA plus 125 bps (computed on a 30/360 basis

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      compounded quarterly) based upon the zero coupon swap curve in effect on
      the date of payment of such amount, as determined by the Calculation
      Agent in accordance with Section 3(b) of the Calculation Agency and
      Interbank Agreement.

      Intermediate Forward Payment Amount means, with respect to any
      Intermediate Forward Payment Date, the USD1,196,976.60 (the USD amount
      as determined by the Calculation Agent according to the following
      formula:

           (Notional Amount - Initial Forward Payment Amount)*((1+r/4)^2 - 1)

           where

           "r" = the fixed rate of interest (computed on a 30/360 basis)
           equivalent, for the period from and including the Effective Date to
           but excluding the Termination Date, to three-month USD LIBOR plus
           125 bps (computed on a 30/360 basis compounded quarterly) based
           upon the zero coupon swap curve in effect on the Effective Date).

      Minimum Advanced Forward Payment Amount means USD2,152,000.00 (the USD
      amount equal to (i) 2.5% multiplied by (ii) the Forward Payment Amount
      minus the FV1 of the Initial Forward Payment Amount).

      PV means, with respect to any Valuation Date and any specified amount,
      the present value of such specified amount, discounted from the
      Termination Date to such Valuation Date at a discount rate per annum
      equal to the fixed rate of interest (computed on a 30/360 basis)
      equivalent, for the period from and including such Valuation Date to but
      excluding the Termination Date, to three-month USD LIBOR plus 125 bps
      (computed on a 30/360 basis compounded quarterly) based upon the zero
      coupon swap curve in effect on such Valuation Date.

      Valuation Dates means each of (i) December 20, 2002 and thereafter the
      last Business Day of each week up to and including December 12, 2003,
      (ii) any Early Termination Date, (iii) any Voluntary Early Termination
      Date and (iv) the Termination Date.

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8. Agreement to Deliver Documents:

      For the purpose of Section 4(a)(ii) of the Agreement, each party agrees
      to deliver the following documents, as applicable:

<table>
<caption>

     -------------------- ------------------------------- --------------------------- ----------------------
     Party required to    Form/Document/                  Date by which to be         Covered by Section
     deliver document     Certificate                     delivered                   3(d) Representation
     -------------------- ------------------------------- --------------------------- ----------------------
<s>                                                                             
     Bank and             Evidence of the authority,      Upon the execution by       Yes
     Counterparty         incumbency and specimen         such party or any Credit
                          signature of each person        Support Provider of this
                          executing any document upon     Confirmation, any Credit
                          behalf of such party or any     Support Document with
                          Credit Support Provider of      respect to such party or
                          such party (including, in the   any other documentation
                          case of Counterparty and each   relating to the Agreement
                          Credit Support Provider,        or any such Credit
                          notarized copies of the         Support Document
                          by-laws of and powers of
                          attorney given by
                          Counterparty or such
                          Credit Support Provider to
                          its officers, as the case
                          may be)
     -------------------- ------------------------------- --------------------------- ----------------------
     Counterparty         Evidence of the appointment     Upon the execution by       Yes
                          of an agent of service of       such party or any Credit
                          process for the Counterparty    Support Provider of this
                          and each Credit Support         Confirmation, any Credit
                          Provider (including copies of   Support Document with
                          appointment and acceptance      respect to such party or
                          letters and powers of           any other documentation
                          attorney (executed in the       relating to the Agreement
                          presence of a Mexican notary)   or any such Credit
                          granted by Counterparty and     Support Document
                          each Credit Support Provider
                          in favor of the process agent)

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     -------------------- ------------------------------- --------------------------- ----------------------
     Counterparty         The Amendment to the Credit     On or prior to the          Yes
                          Support Document with respect   execution by such party
                          to such party specified in      of this Confirmation
                          Paragraph 9 of this
                          Confirmation
     -------------------- ------------------------------- --------------------------- ----------------------
     Bank and             The Amendment to the            On or prior to the          Yes
     Counterparty         Calculation Agency and          execution of this
                          Interbank Agreement             Confirmation
     -------------------- ------------------------------- --------------------------- ----------------------
     Counterparty         Opinion of internal legal       On the Effective Date       Yes
                          counsel of Counterparty and
                          each of its Credit Support
                          Providers, in form and
                          substance satisfactory to
                          Bank, with respect to the
                          matters addressed in the
                          opinion delivered by such
                          counsel in connection with
                          the First Transaction
     -------------------- ------------------------------- --------------------------- ----------------------
     Counterparty         Opinion of Skadden, Arps,       On the Effective Date       No
                          Slate, Meagher & Flom LLP, as
                          counsel to Cemex, in form and
                          substance satisfactory to
                          Bank, with respect to the
                          matters addressed in the
                          opinion delivered by such
                          counsel in connection with
                          the First Transaction

<page>

     -------------------- ------------------------------- --------------------------- ----------------------
     Counterparty         Opinion of Skadden, Arps,       Not later than the tenth    Yes
                          Slate, Meagher & Flom LLP, as   Business Day immediately
                          counsel to Cemex, in form and   succeeding the
                          substance satisfactory to       effectiveness of the
                          Bank, certifying that the       Registration Statement
                          Registration Statement with
                          respect to the Cemex ADS is
                          effective and that no refusal
                          or stop order has been issued
                          by the United States
                          Securities and Exchange
                          Commission
     -------------------- ------------------------------- --------------------------- ----------------------
     Counterparty         Evidence of receipt of any      On or prior to the          Yes
                          necessary Mexican approvals     execution of this
                          by Counterparty and each of     Confirmation
                          its Credit Support Providers
     -------------------- ------------------------------- --------------------------- ----------------------
</table>


9.    Credit Support:

      For purposes of this Transaction only, each of Cemex and Cemex Mexico,
      S.A. de C.V. shall be a Credit Support Provider in relation to
      Counterparty, and the Guarantee, dated as of December 13, 1999 and
      amended as of December 13, 2002, made by the Credit Support Providers in
      favor of Bank shall be a Credit Support Document in relation to
      Counterparty.

10.   Representations:

      In connection with this Confirmation, the Transaction to which this
      Confirmation relates and any other documentation relating to the
      Agreement, each party to this Confirmation (and, with respect to
      Counterparty, Cemex) makes to the other party the representations and
      acknowledgements set forth in Paragraph 15 of the First Confirmation. In
      addition, each party to this Confirmation represents and warrants to the
      other party to this Confirmation that it is an "eligible contract
      participant" as such term is defined in Section 1a(12) of the U.S.
      Commodity Exchange Act.

Counterparty hereby agrees (a) to check this Confirmation carefully and
immediately upon receipt so that errors or discrepancies can be promptly
identified and rectified and (b) to confirm that the foregoing correctly sets
forth the terms of the agreement between
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us with respect to the particular Transaction to which this Confirmation
relates, by manually signing this Confirmation and providing any other
information requested herein and immediately returning an executed copy to
Alejandro Aguilar at +525 259 2701. Hard copies should be returned to Bosque
de Alisos, 45-B, Piso 4, Bosques de las Lomas.


                          Yours sincerely,

                          ING BANK, N.V.


                          By:   /s/ A. B. Rosaria
                              --------------------------------
                              Name: A. B. Rosaria
                              Title:Risk Manager


                          By:  /s/ A.C. Zulia
                              --------------------------------
                              Name: A. C. Zulia
                              Title:Sr. Manager Transaction Processing

<page>

Confirmed as of the
date first above written:

EMPRESAS TOLTECA DE MEXICO, S.A. DE C.V.


By:   /s/ Humberto Moreira
    -------------------------------------------
    Name:  Humberto Moreira
    Title: Attorney-in-fact

Acknowledged and Agreed solely for
purposes of Paragraphs 2, 6, 9 and 10:

CEMEX, S.A. DE C.V.


By:   /s/ Mario de la Garza
    -------------------------------------------
    Name:  Mario de la Garza
    Title: Attorney-in-fact

Acknowledged and Agreed solely for
purposes of Paragraph 9:

CEMEX MEXICO, S.A. de C.V.


By:  /s/ Victor Naranjo
    -------------------------------------------
    Name:  Victor Naranjo
    Title: Attorney-in-fact