The aim of this study was to analyze the pattern of mortality among patients with ulcerative colitis (UC) and compare it with mortality in the general population of the same age and sex. All patients with UC admitted to one of the Inflammatory Bowel Disease Clinics in Rome, from January 1970 to December 31, 1989 were enrolled. Vital status was ascertained through the Registry Office of the last municipality of residence as of July 1, 1990. Cause of death was ascertained through record linkage with the national or regional mortality file and coded using the ninth revision of the International Classification of Diseases. Standardized Mortality Ratios (SMRs) were computed to compare mortality among UC patients with mortality in the general population of the same age and sex. Out of a total of 508 UC patients admitted during the study period, 27 deaths were observed, compared with 27.6 expected (SMR = 98). After excluding prevalent cases, an excess risk of death was observed among newly diagnosed cases in the first year after diagnosis (SMR = 644; p < 0.001); ulcerative colitis was the main reason for this excess mortality. Mortality for other diseases was close to that expected. In conclusion, ulcerative colitis impairs life expectancy in the first year after diagnosis, while no excess mortality seems to be present afterwards.