To assess whether children with inflammatory bowel disease (IBD) develop permanent impairment of linear growth, we analyzed records from 48 young adults who had IBD during childhood or early adolescence (Tanner I-III; 11.8 +/- 2.4 years old at diagnosis). All were fully grown (Tanner V; 21.1 +/- 3.0 years) at last examination. Adult heights were predicted from data obtained at or shortly after the diagnosis of IBD by three methods: height for age percentile, the Bailey-Pinneau (BP), and Roche-Wainer-Thissen (RWT) methods. Predicted adult heights were then compared with the actual ultimate height of each subject. Permanent growth failure occurred in 19-35% of subjects, depending upon the method used to assess growth. Overall, 31% (15 of 48) of the subjects had deficits of adult height identified by two or more methods, including 14 of 38 (37%) of those with Crohn's disease but only one of 10 with ulcerative colitis. Age at diagnosis of IBD, age at last examination, age at cessation of linear growth, and site of IBD did not differ between impaired and normal growth groups. Duration of corticosteroid use was longer (p < 0.05) in growth-impaired subjects. In addition, although 60% of all subjects had periods of poor growth that put them in height-for-age percentiles two or more major growth channels below previous percentiles, only 19% remained at these levels upon achieving their final adult heights. Permanent impairment of linear growth leading to clinically meaningful deficits of ultimate adult height is common in patients with IBD in childhood or early adolescence. New therapeutic approaches are needed to address this problem.