This action research project implemented and evaluated an intervention for increasing prosocial behaviors while decreasing inappropriate behaviors among elementary school children. The targeted population consisted of elementary school students in both lower- and upper-middle-class communities located in central Illinois. The problem of poor social skills was documented by means of behavioral checklists and a social skills inventory. Possible causes for this problematic behavior included inadequate social skills knowledge, inadequate practice using social skills, environmental factors, health problems, and inconsistent expectations for behavior. A review of solution strategies resulted in an intervention which included direct instruction in social skills and the use of cooperative learning structures. Post intervention data indicated an increase in prosocial behavior and a decrease in negative behavior. (Nineteen appendices include daily and weekly behavioral checklists, social skills diagnostic screen data, instructional tactics for teaching social skills, sample lessons, children's literature lists, classroom management plan, and sample forms for classroom use. Contains 37 references.) (Author/SD)