Fetal nutrition is thought to be an important determinant of later disease risk, although evidence from randomized-controlled trials in humans is lacking. We followed children born during a protein-energy supplementation trial to investigate to what extent this maternal supplement, which improved birth weight, influenced offspring body composition in adolescence. Subjects were 1270 Gambian children (659 boys, 611 girls) aged 11-17 y whose mothers had participated in the original cluster-randomized trial and had received the supplement during pregnancy (intervention) or postpartum (control). Basic anthropometry was measured using standard techniques and fatness was assessed by bioelectrical impedance analysis and population-specific prediction equations. For boys, mean body fat was 12.6% for both intervention and control groups. Mean trunk fat was 11.9% in the intervention group and 12.0% in the control. Intervention girls had a mean body fat of 19.5% and trunk fat of 15.2%; for control girls, it was 19.3 and 14.8%, respectively. BMI, body fat, trunk fat, fat mass index, and fat-free mass index did not differ for either sex when analyzed with generalized estimating equations adjusted for age, maternal height, maternal parity, location, season of birth, and menarche in females. Neither infant-attained size nor the onset of menarche were affected by maternal supplementation. These findings suggest that protein-energy supplements to pregnant women, compared with lactating women, do not affect offspring body composition during adolescence.