Mother-infant interaction of 14 teenage mothers and 12 women 20 years or older was observed and recorded in the laboratory or the home when the infants were 16, 20, 24, and 52 weeks of age. In order to assess the possible effect of the research intervention on the maternal behavior and on the infants' development, a control group of teenage mothers and their infants was seen only at the end of the study when the infant was 52 weeks old. At 12 months the Home Observation Measure of the Environment Inventory (HOME) was administered and infants were assessed with the Bayley Scales of Infant Development (motor and mental scales) and the Ainsworth Strange Situation procedure. On all measures the observation groups scored significantly higher than the control group. The significant aspects of the research intervention are discussed.