We studied the associations between early postnatal growth gains and neuropsychological outcome in very preterm-born children. Specifically, we wished to establish whether relationships exist between gains in head circumference (relative to gains in body-weight or length), from birth to hospital discharge, and intellectual, language, or motor, performance at preschool age. We used data from 127 preschoolers, born <33 weeks, all graduates of the William Beaumont Hospital Neonatal Intensive-Care Unit (NICU) in Royal Oak, MI. Cognitive, motor, and language outcomes were evaluated using the Wechsler Preschool and Primary Scales of Intelligence-Revised, Peabody Developmental Scales – 2nd Edition, and the Preschool Language Scale – 3rd Edition, respectively. Differences between Z-scores at birth and hospital discharge, calculated for three anthropometric measures (head circumference, weight, length), were variables of interest in separate simultaneous multiple regression procedures. We statistically adjusted for sex, socioeconomic status, birth weight, length of hospitalization, perinatal complications, and intrauterine growth. Examination of the relationships between anthropometric indices and outcome measures revealed a significant association between NICU head growth and global intelligence, with the Z-difference score for head circumference accounting for a unique portion of the variance in global intelligence (ηp2 =.04). Early postnatal head growth is significantly associated with neuropsychological outcome in very preterm-born preschoolers. To conclude, despite its relative brevity, NICU stay, often overlapping with the end of 2nd and with the 3rd trimester of pregnancy, appears to be a sensitive developmental period for brain substrates underlying neuropsychological functions. (JINS, 2015, 21, 126–136)