The purpose of this study was to identify how effective teachers manage productive groups in elementary grade classrooms. Multiple instrumental case study methods were used to document the managerial actions of selected teachers who made extensive use of cooperative learning (CL) activities. Four teachers in three elementary grade classrooms (two teachers team taught a combined 2nd and 3rd grade class) were selected for further study from a larger sample of 13 teachers. Criteria for teacher selection were based on observations of student engagement and group productivity in the spring of the preceding year. Observations were conducted on 5 to 7 occasions in each chosen teacher's classroom, commencing on the first day of school, except in one class in which group activities were not begun until the second week. Most observations were an hour to an hour and a half in length, and included one or more group activities. After several observations were completed, each teacher was interviewed in order to obtain the teacher's perspective about the use of cooperative learning groups. Additional observations were made later in the school year. Analyses revealed several important features of implementing CL, including planning room arrangement and other aspects of the physical layout to accommodate group work, organizing activities, teaching students procedures and routines for working in groups, and monitoring group activities. The case studies illustrate how effective teachers established their productive CL settings, and the findings should be useful to teachers and teacher educators interested in using CL activities.