This paper describes a longitudinal comparative study of group and family day care for infants in New York City. Approximately 400 infants from low income, predominantly Black or Hispanic families enrolled in publicly or privately funded, community-sponsored day care programs participated in the study from the time they entered the programs (between 2 and 31 months of age) until they reached approximately 3 years of age. Testing for the study was carried out when the children were approximately 6, 12, 18, and 36 months of age. These children were also compared with a control group of children who entered a day care program between 2 1/2 and 3 years of age. The group and family infant programs were studied and compared in three major areas: (1) children's nutrition, physical health, and growth; (2) children's psychological development (social and cognitive); and (3) family development (the impact of the program on the family). Study results suggested better nutrition and health care for infants in group programs as compared to those in family day care. In terms of psychological development, when differences between the groups did occur, they generally favored the family programs over group day care. On Stanford-Binet performance at 3 years of age, however, the group care children obtained significantly higher scores. The study revealed no significant differences in family development between the groups. Specific policy recommendations for improving infancy day care are included at the end of the study. (BD)