Please cite as: "Commentary to Trans-Lex Principle No. XIII.2.1 - Number of arbitrators, http://www.trans-lex.org/968915"

1 The parties can always select the number of arbitrators. Typically, the number is one or three, which avoids a deadlock in the voting of the arbitral tribunal.

2 If the arbitration clause does not contain an agreement on the number of arbitrators, Art. 10 (2) UNCITRAL Model Law provides that the tribunal shall consist of three arbitrators. The same numerical preference is contained in Art. 5 UNCITRAL Arbitration Rules and Art. 6 (1) Swiss Rules. Art. 5.4 LCIA Arbitration Rules, however, follows Sec. 15 (3) 1996 English Arbitration Act and provides, for reasons of cost effectiveness, for the appointment of a sole arbitrator unless the parties have agreed otherwise. Sec. 8 (2) ICC Arbitration Rules provides that absent an agreement of the parties, the ICC Court of Arbitration shall appoint a sole arbitrator, save where it appears to the Court that the dispute is such as to warrant the appointment of three arbitrators. A similar rule is contained in Art. 5 ICDR International Arbitration Rules. This flexible rule makes sense in revealing that the number of arbitrators is not a matter of principle, but depends on the complexity of the dispute and other particularities of the case.