There is widespread acceptance of formalized cooperative learning (CL) programs in the schools. Research evidence of CL's power has been documented, (Vermette, 1998) but there is still an interesting dilemma for early childhood educators: a great deal of the research on CL has been done at grade levels above those holding children from 4 to 8 years old. Thus, as they consider applications to early childhood classrooms, they may ask, "what does the research say about its use for young children?" This article attempts to answer this question by examining several studies that have investigated five key issues related to the effective use of peer-assisted and/or collaborative structures and which shed great insight into teacher decision-making. Our generalized finding was simple: "cooperative learning works." Vygotsky's dictum "what they can do together today, they can do individually tomorrow" holds up under the scrutiny offered by the formal research process.