Medical, neurodevelopmental, and parenting effects of individualized developmental care were investigated in a three-center, randomized, controlled trial. A total of 92 preterm infants, weighing less than 1250 g and aged less than 28 weeks, participated. Outcome measures included medical, neurodevelopmental and family function. Quality of care was also assessed. Multivariate analysis of variance investigated group, site, and interaction effects; correlation analysis identified individual variable contributions to significant effects. The results consistently favored the experimental groups. The following contributed to the group effects: shorter duration of parenteral feeding, transition to full oral feeding, intensive care, and hospitalization; lower incidence of necrotizing enterocolitis; reduced discharge ages and hospital charges; improved weight, length, and head circumferences; enhanced autonomic, motor, state, attention, and self-regulatory functioning; reduced need for facilitation; and lowered family stress and enhanced appreciation of the infant. Quality of care was measurably improved. Very low birth weight infants and their parents, across diverse settings, may benefit from individualized developmental care.