Exhibit 4.1

**Unofficial English translation of agreements originally drawn up in Spanish.  In case of discrepancy the Spanish language version prevails**

**AGREEMENT OF JANUARY 11, 2000 BETWEEN REPSOL YPF AND “LA CAIXA”**

**ANTECEDENTS**

| 1.     | In the year 1990, *Instituto            Nacional de Hidrocarburos* and Repsol, S.A., as party of the first part,            as participants in various            companies in the domestic and commercial gas sector, including Catalana            de Gas, S.A. and Gas Madrid S.A., and, as party of the second part,            la Caja de Ahorros y Pensiones de Barcelona (“la Caixa”),            as main shareholder of Catalana de Gas, S.A., agreed to proceed to            reorder the            activities of the gas sector in Spain and the share ownership of the      existing corporations.                                     |
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| 2.     | On March 5, 1991, INH            and Repsol, S.A., as party of the first part, and “la Caixa,” as            party of the second part, on the basis of their shareholding positions            in the aforementioned            gas sector, agreed to promote the merger of Catalana de Gas, S.A. and            Gas Madrid, S.A., the first taking-over the second, and integrating            within Catalana de Gas, S.A. the share ownership in gas companies belonging            to Repsol Butano, S.A, either through a partial spin-off at the time      of the merger or contribution to Gas Madrid, S.A. prior to the merger.            |
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| 3.     | On December 22, 1993,            once the merger of Catalana de Gas, S.A. and Gas Madrid, S.A. had been            completed, the parties            deemed it appropriate, as a culmination of the iniciated integration            process, for Gas Natural SDG, S.A. (the new name for Catalana de Gas,            S.A. after the merger, hereinafter “Gas Natural”) to acquire            a controlling interest in the capital of Enagás, S.A. (hereinafter            Enagás), with the purchase of 90% of the capital of Enagás            from    INH. Afterwards, in 1999, the remaining 10% was acquired from SEPI. |
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| 4.     | By mutual agreement            the parties negotiated with other relevant shareholders of Gas Natural            for the purchase of their            participations, deciding among themselves that because of the nature            of Repsol S.A. as an industrial partner, that it should be the entity            that would make the purchase. This fact did not alter the agreements      relative to the composition of the corporation’s governing bodies.                                                                                                                                                                                     |
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| 5.     | As a consequence of            all of the previous agreements, the configuration of the governing            bodies of Gas Natural and Enagás,            would be established in the following form (without prejudice to the            rights of minority shareholders who might exercise the right to proportional      representation under Art. 137 of the Law on Corporations):                                                                                                                                                                                                                                                                |

 

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|   | – | The            Board of Gas Natural will be equally composed of members proposed by            Repsol S.A. and those proposed by “la      Caixa”                                                                         |
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|   |   |                                                                                                                                                                                                                               |
|   | – | The            Board of Enagás will have an uneven            number of directors, with a minimum of seven, with Repsol, S.A. having      one director more than “la Caixa”                                       |
|   |   |                                                                                                                                                                                                                               |
|   | – | “La Caixa” will            propose the appointment of the President of both Gas Natural and Enagás,      and Repsol, S.A. will propose the Managing Director, also for both companies.                            |
|   |   |                                                                                                                                                                                                                               |
|   | – | Repsol, S.A. will            also have the power, not exercised to date, of proposing a different            Managing Director for each of the aforementioned companies, and, in that      case, a common Vice President for both. |

 

**OBJECTIVES**

The parties believe it would be appropriate to    adjust the referenced agreements to actual circumstances since Repsol, S.A.    (hereinafter    Repsol-YPF) and Enagás  have been totally privatized and *Instituto Nacional de Hidrocarburos* has been  abolished and replaced by the *Sociedad Estatal de Participaciones Industriales*,  which carried out the aforementioned privatizations. Also the recent Hydrocarbons  Law has established new regulations for gas activities, resulting in a reorganization  of the subsidiary companies of Gas Natural. In addition to all this is the  important international expansion of both Repsol-YPF and Gas Natural, as well  as a trend towards concentration and integration in energy sectors throughout  the world.

All of these factors would suggest that the cohesion    that exists between Repsol-YPF and Gas Natural should be increased, while    trying,    in turn, to maintain its  independence and neutrality as a group vis-à-vis other companies or  groups in the energy sector and to maximize the value of both corporations  for their shareholders.

This contract would permit the integration of Gas Natural into the Repsol-YPF  group, with a consolidation of the financial statements through full consolidation  which would lead to a more exact representation of the economic reality of  Repsol-YPF and its group of companies.

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This new situation would assume a concentrative operation. In order not to      have negative effects on competition, and thus not have undesired effects      on the existing configuration of Gas Natural, it is necessary for the present      agreement to include as one of its basic principles that the new group must      rigorously comply with the requirements of existing legislation in all matters      concerning Defense of Competition. It must maintain full neutrality, avoid      any discrimination with regard to the electric companies or any other activity      in which Repsol-YPF, Gas Natural or its subsidiaries may be competitors,      suppliers or providers of goods or services. It must also have internal safeguards      or barriers that are necessary to avoid any possible anticompetitive effect      on client information.

All of the circumstances set forth would indicate that the previous agreements  should be rendered null and void and replaced by the following

**AGREEMENTS**

**FIRST. BOARDS OF DIRECTORS      OF GAS NATURAL ANDENAGÁS**

A) **Boards of Gas Natural        andEnagás******

I.- The Board of Gas Natural

 Repsol-YPF and “la Caixa” undertake    to exercise their voting rights at the General Shareholders' Meetings of    Gas Natural    to establish the following  composition of the Board of Directors for that company:

|   | a)     | The number of directors will be uneven, and          barring a new agreement by both parties, will consist of 11 members.    In any case, it will comply with the maximum established in the Bylaws.                                                                                   |
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|   |   |                                                                                                                                                                                                                                                                                   |
|   | b)     | Both parties will try to appoint as many          members as possible to the Board of Directors, from the total number          established by the Shareholders' Meeting, in full compliance with the    rights assigned to other shareholders by Art. 137 of the Law on Corporations. |

 

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|   | c)     | Repsol-YPF          will have the right to propose, and “la Caixa” will undertake to          vote in favor of this proposal, 6 Members of the Board of Directors if          there are 11 members, or the majority of any uneven number established          by each Shareholders’ Meeting, as the case may be. “la Caixa” will          have the right to propose the rest of the appointments, and Repsol-YPF          will undertake  to vote in favor of this proposal.                                                                                                                                                          |
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|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|   | d)     | In          the event that one shareholder or group of shareholders, exercising          the right granted          by Art. 137 of the Law on Corporations, whether in the form set forth          in Royal Decree 821/91 or through consensus with the other shareholders,          should appoint one or more directors, the parties, by mutual agreement,          will adjust the number of members and composition of the Board so that          they can fulfill the objective sought and, to the extent possible,          keep the equilibrium between the directors designated by Repsol-YPF          and those    designated by “la Caixa” |
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |
|   | e)     | If          directors are appointed by the Board itself to fill vacancies produced          during each          fiscal year, then directors appointed by each of the parties will follow          the same criteria set forth in paragraph (c) above for appointments    made by “cooptación”.                                                                                                                                                                                                                                                                                                                                               |

II.- Board of Enagás

 The parties will exercise their political rights    in Gas Natural so that the directors of Enagás, an uneven number and a minimum of seven, will be  appointed from those persons proposed by Repsol-YPF and by “la Caixa”,  with Repsol-YPF appointing one more director than “la Caixa” 

  B) **President and Managing Director at Gas Natural and Enagás**

“la Caixa” will propose someone to fill    the position of President of the Board of Directors from among the directors    that it proposed,    and Repsol-YPF  will propose someone to fill the position of Managing Director from among the  directors that it proposed, with both parties agreeing that the directors proposed  and appointed by each will vote in favor the designation of these positions  within the Board pursuant to the appointment power recognized herein.

 

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C) **Executive Commission        of Gas Natural and Enagás**

The Executive Commission of Gas Natural and Enagás will be made up  of five members, three of whom will be proposed by Repsol-YPF and two by “la  Caixa”. One of those proposed by “la Caixa” must be the President,  who will also chair the Executive Commission, and one of those proposed by  Repsol-YPF must be the Managing Director.

**SECOND. COMMITTEES WITHINTHE BOARD OF DIRECTORS OF GAS NATURAL**

In addition to the Executive Commission on the Board of Gas Natural, a Nomination  and Compensation Committee and an Audit and Control Committee will also be  maintained on this company’s Board of Directors. Neither of these Committees  will have delegated powers. Their functions will be to make studies and proposals. 

Each of these Committees will be composed of four members elected by half  of those proposed by each of the parties who sign this contract.

The Nomination and Compensation Committee will    be chaired by one of the directors appointed at the proposal of Repsol-YPF    and the Audit    and Control Committee  by one of the directors appointed at the proposal of “la Caixa”

The President of the Committees cannot have the deciding vote.

**THIRD. THE PRESIDENT ANDMANAGING DIRECTOR OF GAS NATURAL AND ENAGAS**

**A)	President**

The President of the Board will exercise the functions assigned to this position  by the Law on Corporations and by the company Bylaws. Among other things, this  includes the following:

|   | – | Chairing          the Board of Directors and the Executive Commission, as well as the    General Shareholders’ Meeting.                                                                                                                       |
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|   |   |                                                                                                                                                                                                                                               |
|   | – | Convening the Board          of Directors, verifying that the requirements for valid constitution          of the Board have been met, and declaring it validly constituted, as    well as authorizing attendance by persons other than directors. |
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|   | – | Directing deliberations          by the Board of Directors and, after matters have been debated, submitting          them to a vote, deciding the format thereof, and announcing the final        results.  |
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|   | – | Extending or suspending        Board meetings, as well as adjourning these.                                                                                                                                 |
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|   | – | Signing the minutes    of the Board meetings, and approving certifications of resolutions.                                                                                                                  |
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|   | – | Acting as spokesperson          for the Board of Directors and assuming the role of institutional representative    of the company.                                                                         |
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|   | – | Executing the resolutions    of the Board of Directors, when deemed appropriate.                                                                                                                            |
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|   | – | Ensuring          that the Board’s resolutions are complied with and that the shareholders’    and board members’ rights to information are fulfilled.                                       |
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|   | – | Coordinating the          activity of the members of the Board of Directors and the committees          thereof, and ensuring that it is adjusted to the decisions and planning    undertaken by the Board. |

**B)	Managing          Director**

The Managing Director will manage and administer the company. As a result,  all of the powers of the Board of Directors that can by law be delegated will  be delegated to him. Among other things, these include:

|   | – | Managing and administering the company.                                                                      |
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|   |   |                                                                                                         |
|   | – | Executing the resolutions passed by the Board    of Directors, if necessary.                                 |
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|   | – | Managing personnel.                                                                                          |
|   |   |                                                                                                         |
|   | – | Implementing and developing the resolutions    passed by the Board of Directors or the Executive Commission. |

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|   | – | Technological development, commercial policies          and financial management, pursuant to the decisions, planning and strategy    decided by the Board of Directors or the Executive Commission. |
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|   |   |                                                                                                                                                                                                 |
|   | – | Coordinating policies on natural gas for          the Repsol-YPF group, attending meetings of the Executive Committee of    Repsol-YPF, if deemed appropriate.                                       |

**FOURTH. REGISTERED OFFICEOF GAS NATURAL**

The corporate seat and domicile for tax purposes of Gas Natural will continue  to be in Barcelona, with central services of the entire group divided between  Barcelona and Madrid.

**FIFTH. PRINCIPLES OF INDUSTRIALACTIVITY**

To further the objectives indicated in the general declarations of this document,  which the parties understand are of interest to Gas Natural and Repsol-YPF,  and to achieve these through participation in the governing bodies of both  companies, they undertake and agree to:

A)	****Exploration            and Production****

The activity of exploration and production, as well as ownership of the reserves,  corresponds to Repsol-YPF. Notwithstanding this fact, Gas Natural will be responsible  for the acquisition of up to one-third of the gas reserves in Trinidad and  Tobago that BP-Amoco makes available to the Repsol-YPF group in fulfillment  of signed contracts.

B)	****Subterranean storageof natural gas****

Gas Natural will have a majority holding in the future activities of subterranean  storage of natural gas, whether these are carried out directly or through the  constitution or creation of corporations. In any case, Repsol-YPF will act  as the technical operator with regard to the search for locations and construction  of installations, and Gas Natural with regard to management of storage.

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C)	****Logistics            of supplying natural gas****

Gas Natural will be in charge of the implementation and management of the  logistics of supplying natural gas to its markets from the fields of third  parties outside the Group, and from the fields of Trinidad and Tobago, in proportion,  in this case, to the reserves that Gas Natural may have, pursuant to the principle  of Paragraph A).

Repsol-YPF will be in charge of implementation and management of the logistics  of supplying gas in other cases.

D)	****Transport,            distribution and storage of natural gas****

Gas Natural, directly or through its specialized subsidiaries, will be the  owner and operator of the installations for regasification, interior transport,  distribution and commercialization of natural gas within Spain and outside  of Spain. Direct ownership by Repsol-YPF will occur as an exceptional case  when there are specific reasons for it, when Repsol-YPF has already assumed  ownership, or when the means of transport are related to Repsol-YPF’s activity  of exploration or production.

E)	****Participation in naturalgas companies and assets****

Gas Natural will be the purchaser of companies and assets for transport, distribution  and commercialization of natural gas, except in those cases when the companies  or assets are derived from the activities of exploration and production corresponding  to Repsol-YPF pursuant to the principles of this contract. 

In those cases when buying opportunities arise that may be of interest to  Repsol-YPF within the overall gas chain, but are not of interest to Gas Natural  in its basic activity of distribution of natural gas, then appropriate procedures  will be established so the opportunity is not lost, without any negative financial  consequences to Gas Natural and Repsol-YPF.

F)	****Electricity****

Both Repsol-YPF and Gas Natural    will support decisions on electric power generation that either of the two    companies deems worthwhile.

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**SIXTH. TERMINATION AND MODIFICATIONOF THE AGREEMENT**

|   | A)     | This agreement will terminate if either of    the following events should occur:                                                                                                                                                                                                                                                                                                                                                                                |
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|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                            |   |   |
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                            | – | Participation of “la Caixa” in          the capital of Gas Natural falls below 25% at any time as a consequence    of the sale of all or part of its shares. |
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                            |   |   |
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                            | – | Participation of    Repsol-YPF in the capital of Gas Natural falls below 25% at any time. |
|   |   |                                                                                                                                                                                                                                                                                                                                                                                                                                                            |   |   |
|   | B)     | If          the participation of Repsol-YPF in Gas Natural is at least 25%, but          falls below 35%, these          agreements will continue in effect, except with regard to the composition          of the Board of Directors and the Executive Commission of Gas Natural.          As of that moment, the same number of persons will be appointed at          the proposal of Repsol-YPF and at the proposal of “la Caixa” to    the Board. |

 

**SEVENTH. EFFECTIVENESS**

The effectiveness of this agreement is subject to compliance with the following  conditions precedent:

1) This contract must be approved, or not give rise to any objections, in  its entirety and unconditionally, by the authorities both in Spain and, if  applicable, in the European Community, who are competent within the area of  Competition Regulations.

2) “la Caixa” must be able to make some arrangement with Banco de  España that will enable it to keep its actual level of investments in  Repsol-YPF and Gas Natural, without being penalized for the actual situation,  its coefficients of proprietary assets and other ratios as a result of the  concentrative process that the change in the composition of the Board of Gas  Natural, as agreed to herein, would cause.

3) These agreements do not constitute    an obligation to formulate a tender offer for the shares of Gas Natural.

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4)        Approval hereof by the Boards of Directors of Repsol-YPF and “la        Caixa”

As a result, unless the four conditions precedent are met, this agreement  will not become effective.

**EIGHTH. REPORTING TO THESECURITIES AND EXCHANGE COMMISSION**

This contract will be reported to the National    Stock Market Commission (*Comisión  Nacional del Mercado de Valores*) and to the markets, and published as a significant  event.

As evidence of their conformity, both parties have signed on the indicated  date, January eleventh, two thousand.

| REPSOL, S.A.                      | CAIXA D'ESTALVIS I PENSIONSDE BARCELONA |
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| Signed:Alfonso Cortina de Alcocer | Signed:Josep Vilarasau Salat            |

 

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