A 5-yr-old child with isolated combined pancreatic lipase and colipase deficiency is described. The patient has a history of passing oily stools since birth. Pancreatic stimulation tests showed that both lipase and colipase activities were less than 2% of normal control values. Despite the total lack of both enzymes, the patient's fat absorption coefficient was 50%. Fat absorption coefficient increased to 82% with pancreatic enzyme supplementation. This is the first report of congenital combined lipase and colipase deficiency.