The effects of cooperative learning on 417 regular-education students, acceptance of 41 of their special-education classmates were examined in an 8-month study. The participants were in Grades 5-8 in 21 classes in 2 U.S. schools. The 3 conditions were cooperative learning and competitive learning, taught by the same teachers, and competitive learning, taught by a random sample of teachers. In October and in May, the regular-education students rated each classmate's desirability as a work partner. The students' peer ratings were generally very stable, for both their regular-education classmates and their special-education classmates. Positive changes in peer ratings for both types of classmates occurred more frequently in the cooperative-learning condition than in the competitive-learning conditions.