This study tested the hypothesis that a 6-month, half-day program of enrichment in language and Piagetian sensorimotor skills tailored to the cognitive-developmental level of infants would accelerate the development of participating infants. The experimental population consisted of 16 12-month-old infants attending enrichment sessions at Syracuse University's Children's Center. The control group consisted of 16 12-month-old infants who received no intervention. All the infants were black and from low income homes. The tests used in assessment were: a standardized infant global IQ test, the Cattell Infant Intelligence Scale, the Early Language Assessment Scale, and the Piagetian Infancy Scales. The results demonstrated that females benefited more than males from the enrichment program, possibly due to differential home treatment. The advances made by the experimental infants both on the Object Permanence Scale and the Means-Ends Scale compared to their controls offers encouragement to explicitly planned enrichment efforts, based on a Piagetian cognitive-developmental model and designed to offset cognitive deficits that sometimes result when an infant is not provided the variety, sequencing and challenge appropriate to his level of experiences. (AJ)