Background Early childhood malnutrition is associated with cognitive and behavioral impairment during childhood and adolescence, but studies in adulthood are limited. Methods Using the NEO‐PI‐R personality inventory, we compared personality profiles at 37–43 years of age (M 40.3 years, SD 1.9) of Barbadian adults who had experienced moderate‐to‐severe protein‐energy malnutrition (PEM) in the first year of life (n = 77) with healthy controls, who were former classmates of the index cases and were matched for age, gender, and handedness in childhood (n = 57). The previously malnourished participants had been rehabilitated, with good health and nutrition documented up to 12 years of age, and study participants were followed longitudinally from childhood to 40 years. Group comparisons were adjusted for childhood and adolescent standard of living, with and without correcting for IQ. Results At the broad domain or factor level, previously malnourished participants had higher scores on Neuroticism and lower scores on Extraversion, Openness, Agreeableness, and Conscientiousness than did the healthy controls. At the subdomain or facet level, previously malnourished participants reported more anxiety, vulnerability, shyness and lowered sociability, less intellectual curiosity, greater suspiciousness of others, a more egocentric than altruistic orientation, and a lowered sense of efficacy or competence. Conclusions Malnutrition limited to the first year of life with good health and nutrition documented up to 12 years of age is associated with a significant overrepresentation of adult personality trait scores outside of the average range. This outcome has important implications for a variety of important life and mental health outcomes.