Growth failure in children and young adults with Crohn's disease (CD) is well documented, but few studies of sufficient size have examined its correlates including nutritional status and body composition. 132 subjects with CD and 68 age-matched healthy controls, 6 to 25 years of age, were examined with respect to growth, nutritional status, body composition (BC) and sexual and skeletal maturation using standard techniques. Ht was adjusted for parental stature by mid-parental ht tables (Himes et al). Z-scores for growth and nutritional status were calculated using NCHS data. Percent body fat(%BF), fat mass (FM) and fat free mass (FFM) were measured by Dual Energy X-Ray Absorptiometry (DEXA) and calculated from anthropometric prediction equations using 4 skinfolds (4SF's) thickness measurements. Comparisons between groups was performed by t-test or ANOVA. Significance was defined at the p<0.05 level. Subjects with CD and controls were similar in age, weight and height. Subjects with CD had significantly lower ht z-score (-0.70 vs. 0.07), parent adjusted ht z-score (-0.91 vs. 0.07) and wt z-score (-0.48 vs. 0.36) than controls. There was no difference in any z-score measure by Tanner stage within the CD group. Males with CD were significantly shorter and thinner than females with CD (parent adjusted ht z-score, -1.07 vs. -0.62; wt z-score, -0.68 vs. -0.14). Two indicators of nutritional status, arm circumference (-0.42 vs. 0.02) and subscapular z-scores (-0.30 vs. -0.08) were lower in subjects with CD than controls. Males with CD (vs. control males) accounted for this significant difference and also had a decreased elbow breadth z-score (-0.67 vs. 0.05). Within the group of males with CD, these decreases in elbow breadth and arm circumference z-score correlated significantly with delayed bone age, reflecting the effects of delayed sexual maturation. Overall, there was no difference in body composition by DEXA or 4SF between subjects with CD and controls. However, females with CD (vs control females) had a higher% BF by DEXA (32 vs. 24) and by 4SF's (26 vs. 22) even after correcting for age and Tanner stage. In conclusion, much of the growth failure and poor nutritional status seen in this group with CD was accounted for by males, with females having more normal status.