Diarrhea is a difficult diagnostic problem in patients with chronic graft-versus-host disease (cGVHD) because there are many causes of it. Although intestinal involvement has been reported in early studies of untreated cGVHD, this is now a very rare presentation of the disease. In addition to other etiologies, pancreatic insufficiency should also be considered in patients with cGVHD who demonstrate malabsorption. The pathogenesis of pancreatic insufficiency in these patients is unknown. Pancreatic enzyme supplements can be very effective in treating this rare condition.