Accumulating data on early intervention for preterm infants illustrated short-term benefits on enhancing child development and decreasing parental stress, particularly for those of heavier birth weights. However, rare studies had designed early intervention program for small preterm infants and longitudinally examined the effectiveness in various outcome domains. Our research team recently conducted a clinical randomization trial on the effectiveness of three early intervention programs: usual care program (UCP), clinic-based intervention program (CBIP) and home-based intervention program (HBIP) on very low birth weight (VLBW, birth weight <1,500 g) preterm infants from the neonatal period to two years corrected age (CA). The latter two were comprehensive, intensive intervention programs that combined child- and parent-focused services beginning in hospitalization and ending at one year CA as delivered at clinic and home respectively. This three-year research project has extended our previous work to longitudinally examine the effectiveness of the three intervention programs in 180 VLBW preterm infants at 3 and 4 years of age. Sixty full-term infants will also be included to serve as the reference group. Outcome measures will include child (i.e., health, growth, neurodevelopment and behavior), parenting (i.e., parental stress, competency, efficacy and family support) and mother-child transactions (i.e., free-play and frustrating episode). The longitudinal data on the effectiveness of these early intervention programs for VLBW preterm infants will provide important information to help early intervention professionals and public policy makers to develop effective intervention for preterm children at risk for developmental problems.