This chapter describes how cooperative learning provides one means of making the best of the less than ideal situation that teachers face when facilitating learning in large classes. The chapter begins with a description of some of the difficulties teachers confront when using group activities with large classes. Next, background on cooperative learning is presented, including theory, research, principles, differences between cooperative learning and traditional group activities, and details of a few cooperative learning techniques. The rest of the chapter offers practical solutions to problems and concerns of teachers who use cooperative learning in large classes. These include matters such as how to form groups, getting students' attention when they are working in their groups, arranging the seating of groups, dealing with the noise level, selecting cooperative learning techniques appropriate to large classes, and delegating responsibility to students. [This article was published in M. Cherian & R. Mau (Eds). "Large Classes," p142-157 2003. Singapore: McGraw-Hill.]