Two hundred and fourteen patients with Crohn's disease (CD) consecutively admitted during a 5-year period were observed for a mean of 9 years (range, 0-35 years). Sixty-five per cent had their initial symptoms between 10 and 30 years of age and 9.2% after the age of 50 years. The CD diagnosis was delayed for more than 10 years in 8% (mean, 4.5; range, 0-31 years). Large-bowel involvement was seen in 82.5% and was the only localization of the disease in a fourth of the patients. Recurrent abdominal pain occurred in two-thirds of patients with ileal or ileocolic disease. Acute abdominal pain was the cause of laparotomy in 14% of the patients with ileocolic CD. Diarrhea and rectal bleeding occurred significantly more often in colonic CD, whereas fistula complicated ileocolic disease more often than isolated involvement of small or large bowel. Associated extraintestinal diseases were seen in 117 patients (55%), most frequently related to colonic involvement (joint disease, 21%; eye, 12%, skin, 8%). Of 26 patients (12%) with liver pathology, 10 patients had amyloid deposits. Amyloidosis was diagnosed in altogether 12 patients (6%).