Delayed puberty frequently complicates the clinical course of young patients with inflammatory bowel disease, more often in Crohn's disease than ulcerative colitis. Undernutrition has been thought to be the main reason for delayed puberty in these patients. However, puberty may be delayed despite a normal nutritional status. Observations in patients with inflammatory bowel disease and in rats with experimental colitis suggest that inflammatory mediators may have a direct adverse influence, independent of undernutrition, on the onset and progression of puberty. Serum androgens are consistently reported to be reduced in patients with delayed puberty and inflammatory bowel disease. This reduction is not necessarily secondary to a reduction in gonadotrophins as serum concentrations of gonadotrophins have been reported to be normal or even increased in some studies. Management of delayed puberty involves calorie supplements to correct undernutrition and treatment of inflammation. Observations in boys with delayed puberty and controlled studies in experimental models of intestinal inflammation suggest that testosterone therapy can accelerate puberty.