The continuing contribution of early biological and psychosocial risk factors to developmental outcome of 55 very low birth weight infants (≤ 1500 g) was assessed at 4 years of age. Biological risk, assessed by the Neurobiologic Risk Score, accounted for significant portions of the variance in the perceptual-performance (17%) and motor (35%) dimensions of the McCarthy Scales of Children's Abilities. Psychosocial risk, reflected in maternal appraisals of daily stress during the newborn period, did not account for a significant portion of variance in any of the McCarthy Scales. Maternal education level, however, another measure of psychosocial risk, accounted for significant portions of variance (from 6% to 34%) on each of the McCarthy Scales. Movement from low neurobiologic risk status to poor outcome status at 4 years of age was associated with a number of psychosocial variables, including maternal education and early levels of maternal daily stress. The findings are discussed in terms of early markers for very low birth weight infants who require careful follow-up and of potential intervention targets to promote developmental outcome.