Developmental data were obtained on 40 children with Down's syndrome by an interdisciplinary team during an ongoing early intervention program. Interventive methods are described. Results are compared with available data on children with Down's syndrome who were not in early intervention programs. Comparisons of developmental progress are also made of children begun in the early intervention program before six months of age with those begun after six months of age. Conclusions from the study indicate that early intervention helps the child in earlier attainment of many developmental tasks and enhances functioning of the family unit.