A multivariate study investigated developmental progress in very low birth weight infants (VLBW ≤ 1,500 grams) during the first year of life. The subjects were 41 VLBW infants (Mbirth weight = 1,203 grams) who were free from congenital anomalies and appropriate for gestational age. Eighteen infants were male, 23 were female. Data were gathered from the infants' charts and during home visits when the subjects were 6 and 12 months corrected gestational age. Birth weight, intraventricular hemorrhage status, number of days supported by mechanical ventilation, number of days in the intensive care nursery, socioeconomic status, and characteristics of the childrearing environment were examined in relation to developmental progress. Data were analyzed using multiple regression analysis and cross-lagged panel analysts. Environmental factors were powerful influences accounting for 67% of the variance in development at 1 year. Cross-lagged panel analysis suggested a causal relationship between the quality of the home environment and developmental achievement at 1 year.