We study the effects of truncation on the performance of an open matrix–at–a–time sequential sampling procedure [d], described by Bechhofer and Goldsman (1987a) for selecting the normal population which has the largest mean, when the variances of the populations are known and equal. This procedure which was devised for 2–factor experiments with no interaction between the factor–levels is a generalization of the basic procedure [d] proposed by Bechhofer, Kiefer and Sobel (1968) for single–factor experiments. The performance of a truncated version [d] of [d] is compared to that of [d] as well as to [d] the single–stage procedure of Bechhofer (1954). The performance characteristics studied for the sequential procedures include the achieved probability of correct selection (P{CS})