This paper is a report of a year-long school-based study in Singapore that investigated the effects of the use of cooperative learning in elementary social studies classrooms on social studies achievement, attitude towards the subject, and classroom climate. Results indicated that lower ability pupils benefited the most from the use of cooperative learning in social studies lessons. These students had better social studies test scores than the control class and did just as well as the high ability pupils on the recall items of the test. Attitude towards the subject in the experimental classes did not decline over the school year, but attitude towards the subject in the control classes declined significantly. There were no significant differences between experimental and control classes in classroom climate. Results have provided some evidence to support the use of cooperative learning in Singapore schools. Contains 7 tables of data, 18 citations of research studies of cooperative learning in social studies, and 21 references. (BT)