Noting children's limited opportunities for cross-age interaction, this paper discusses the benefits of mixed-aged groupings of preschool and elementary school children for social and intellectual development. The benefits for older children and younger children are considered in turn, and general benefits to both groups and their adult caregivers are also discussed. The paper notes that, in general, the potential benefits of mixed-age groups represent life skills not considered on state achievement tests. These skills include learning at an early age how to offer comfort, to read to and for those who cannot yet do so, learning how to request assistance from more competent peers, and engaging in more complex play and problem solving. (JPB)