This report presents outcome data on infant motor activity and behavioral state. Subjects were 45 infants who had birth weight of less than 1,501 grams, were appropriate for gestational age, and were free of major complications. A total of 21 infants were studied during a preintervention (control period), and 24 were studied in a posttraining (study period). Staff nurses were trained to: (1) lower light and noise levels and create diurnal patterning; (2) support motor development by maintaining flexed posture and by containing diffuse activity; (3) support behavioral state organization by protecting sleep periods; (4) facilitate feeding by offering a pacifier during gavage feeding; and (5) reduce procedural stress by pacing interventions and providing containment. Unit organization was monitored weekly. Light and noise levels were measured biweekly. Infant and nurse behavior were sampled at 30-second intervals during biweekly 18-minute observations of routine care. Results demonstrated that developmental care can improve both behavioral organization and medical and growth outcomes. It is concluded that the positive effects for motor activity and behavioral state have special relevance for social and cognitive development. (RH)