Relative survival up to December 31, 1986 was analyzed for all patients diagnosed with ulcerative colitis (UC) (n = 2,509) and Crohn's disease (CD) (n = 1,469) within the Uppsala Region, Sweden 1965-1983. After 10 years survival was 96% of that expected for UC and CD. Patients with ulcerative proctitis, left-sided colitis, and pancolitis at diagnosis had relative survival rates of 98%, 96%, and 93% respectively. Survival did not differ by extent at diagnosis for patients with CD. After including prevalent cases, 684 deaths occurred compared with 481.1 expected deaths [standardized mortality ratio (SMR) = 1.4; 95% confidence interval (CI) = 1.3-1.5]. Inflammatory bowel disease was the main reason for this excess mortality. Colorectal cancer increased mortality (50 deaths observed vs. 15.2 expected). Death from other cancers were not greater than expected. Obstructive respiratory diseases, especially bronchitis, emphysema, and asthma increased mortality SMR = 1.5 (95% CI = 1.1-2.2) in UC. Cerebrovascular disease mortality occurred less often than expected (SMR = 0.7; 95% CI = 0.5-1.0). Mortality for other diseases and groups of diseases was close to that expected.