BACKGROUND: Amyloidosis (A) is a well-known but rare complication to inflammatory bowel disease (IBD). We describe 18 patients with IBD and A, with special emphasis on clinicopathologic features and site relationships, comparing our results with previously reported cases in the world literature. METHODS: Patient records were collected from the files of the medical department at Rikshospitalet. Clinical data were compiled from records. RESULTS: Fifteen of the 18 patients had Crohn's disease (CD), 1 had ulcerative colitis (UC), one had UC preceding CD, and 1 had indeterminate colitis. There was a male preponderance of 13:5 = 2.6. Five of the patients had A at the time of diagnosis of IBD. Median time from diagnosis of IBD to A was 4 years, and A was diagnosed within 5 years after onset of IBD in 11 patients. Thirteen of the patients had suppurative complications; 12 had extraintestinal manifestations. Sixteen of the patients had been treated by bowel resection, 14 due to refractory IBD. Ten patients had been treated by renal transplantation. After 15 years of follow-up, the survival rate was 60%. CONCLUSIONS: Our findings strengthen the previous impression of an approximately 3-fold increased preponderance in males, with at least 10-fold increased frequency in CD compared with UC, and with a possible relationship to suppurative complications and extraintestinal manifestations, as well as an increased risk of having a bowel resection. The increased survival seems to be due to the introduction of renal transplantation.