The arbitration agreement shall be in writing. An agreement is in writing if it is contained in a document signed by the parties or in an exchange of letters, telex, telegrams or other means of telecommunication which provide a record of the agreement, or in an exchange of statements of claim and defence in which the existence of an agreement is alleged by one party and not denied by another. The reference in a contract to a document containing an arbitration clause constitutes an arbitration agreement provided that the contract is in writing and the reference is such as to make that clause part of the contract.

This provision echoes the principle established by the Convention on the Recognition and Enforcement of Foreign Arbitral Awards, New York, 1958, Art. II(2):

The term “agreement in writing” shall include an arbitral clause in a contract or an arbitration agreement, signed by the parties or contained in an exchange of letters or telegrams.

A certain difference is notable between these two rules. The last sentence of the Uncitral Model Law provision is intended to clarify a matter which, in the context of the New York Convention 1958, has led to problems and divergent court decisions. It deals with the not infrequent case where parties, instead of including an arbitration clause in the contract, refer to a document (e.g., general conditions or another contract) containing an arbitration clause.