Analyses of the peak and predominant toy play of 17 preschool children with mental retardation and 17 preschool children without mental retardation are presented. Groups were matched on developmental age and sex and observed during both a home-based independent play situation and classroom-based free play. Results are presented for 1) a comparison of predominant play between setting for each group, 2) a comparison of peak play between setting for each group, 3) between-group analyses of predominant and peak play, and 4) a comparison of predominant and peak play. The results provide additional support for, and extend efforts to understand, contextual variation of children's toy play by demonstrating an advantage of home-based play over classroom-based play for both groups as well as an advantage of children with mental retardation over children without mental retardation during the home-based play situation. These data can be used to promote positive perceptions of, and attitudes toward, children with mental retardation among both parents and teachers, and to promote the use of a comprehensive, multi-contextual understanding of children's play ability and potential that is necessary for developing effective interventions. (Contains 7 tables.)