109 Children were classified using the Ainsworth Strange Situation at 18 months. 81 children who were unequivocally classified as insecure/avoidant (A1, A2) or securely attached (B1, B2, B3) were used in this study. The children's parents reported on occurrences of problem behaviors at 24 months, 27 months, 30 months, and 48 months using several methods. The children were observed at 18 and 30 months in their homes with their families and in toddler playgroups during the same period. The only significant effect for attachment classification was that teachers and observers of the playgroups rated girls classified as insecure/avoidant as more difficult to deal with and as having more difficulty with peers than girls rated as securely attached.