In a consecutive series of 107 patients operated on for Crohn's disease involving the distal ileum, the overall incidence of gallstones was 17% and of renal stones 12%. Whereas the frequency of gallstone disease was 9% in patients with minor resections, patients with more than 100 cm diseased or resected small bowel had a frequency of 35%. The probability of gallstone development in both sexes was calculated to be approximately 50% after 20 years of distal ileopathy. The frequency of renal stone disease in patients with minor resection was comparable to that of a population in Sweden but was significantly commoner in patients with resection of more than 100 cm (28%), provided they were not colectomized. The high frequency of stone disease after resection of distal ileum is attributed to metabolic disturbances due to steatorrhea and bile salt malabsorption.