Short stature is a common complication of inflammatory bowel disease. Recently McCaffery, Nasr, Lawrence, and Kirsner (1970) concluded, from blood growth hormone (GH) levels obtained during insulin-hypoglycaemic provocation, that GH deficiency contributed to the retardation in growth observed in subjects with inflammatory bowel disease. Although it was not possible to eliminate the possibility of partial hypopituitarism, this study does not confirm the existence of GH deficiency in six subjects with short stature complicating inflammatory bowel disease. The nyctohemeral (night and day) serum GH is described, and the insulin and glucose levels in these subjects and normal sleep-related GH rises in all are demonstrated. This finding is not compatible with growth hormone deficiency. In one subject the response to arginine provocation was blunted. Three subjects manifested hyperinsulinism and evidence for ;insulin resistance'. These findings are unexplained but suggest that insulin resistance may contribute to a blunted GH response to insulin-induced hypoglycaemia. Blunted GH response to both arginine and insulin-induced hypoglycaemia may also result from continuous secretion and reduced pituitary storage of growth hormone. This possibility is suggested by the pattern of raised blood GH levels in one of the subjects.