This study compared the social interaction and types of symbolic play found in mixed-age and same-age preschool groups. The sample included 8 groups of 14 to 20 children, which were naturally formed and had been operating since the beginning of the school year. The four same-age groups included a group of 3- to 4-year-olds, a group of 4- to 5-year-olds, a group of 5- to 6-year-olds, and a group of 6- to 7-year-olds. The four mixed-age groups consisted of children between 3 or 4 years and 7 years. Each group was videotaped during spontaneous play. All play sequences classified as symbolic were selected and analyzed for content, degree of complexity, and the wholeness of the symbolic transformation using McLoyd's evaluation scheme. This scheme included the following categories: (1) animation; (2) reification; (3) attribution of object property; (4) substitution; (5) object realism; (6) attribution of non-existent object property; (7) situation attribution; and (8) role attribution. Findings indicated that children in mixed-age groups achieved higher forms of symbolic transformation than their peers in same-age groups and that role and situation attribution occurred more frequently in mixed-age groups. The study also found that children in mixed-age groups engaging in role play spent relatively long periods of time in that type of play and that children changed roles within the play sequences regardless of their age. (Contains 16 references.) (KDFB)