Objective: To study the developmental, behavioral, and medical features in a cohort of Romanian children adopted by Manitoba families. Design: A prospective longitudinal study. Setting: The Child Development Clinic, Children's Hospital, Winnipeg, Manitoba, from September 1990 to June 1992. Patients: Developmental, behavioral, and medical features were assessed in 22 Romanian children adopted by 18 Manitoba families. Results: Mean (+/-SD) age at adoption was 15.5+/-13 months. Mean (+/-SD) age at initial assessment was 19+/-12 months and at follow-up, 35+/-13 months. Medical complications included 6 children (27%) who were positive for the hepatitis B surface antigen, 5 with intestinal parasites (23%), 1 positive for the human immunodeficiency virus, I with rickets (5%), and 1 with monoplegia and cleft palate (5%). Initial growth parameters were less than the fifth percentile for age for head circumference in 10 children (45%), for weight in 8 (36%), and for height in 7 (32%). At follow-up, statistically significant improvement was seen in height and weight. Initial mean (+/-SD) developmental quotients were 82+/-20 for gross motor, 83+/-23 for fine motor, 83+/-19 for cognitive, and 79+/-18 for language domains. Follow-up mean developmental quotients improved in all domains (P<.05). Twelve children (55%) displayed abnormal behavior at the initial assessment; behavioral findings persisted in 8 (36%). Initial appropriate activity level and play behavior predicted normal cognitive outcome (P<.05). Conclusions: This longitudinal study of Romanian adoptees delineates improvements in growth and development once the children are placed in a nurturing environment. The persistence of abnormal behavior in, some children underscores the importance of further follow-up.