The major operative indication for ulcerative colitis is intractability. Although steroid side effects appear to be closely associated with surgical indications for intractable ulcerative colitis, this relationship has yet to be analyzed in detail. To elucidate this relationship, we investigated 39 surgical patients with intractable ulcerative colitis, as defined by the Research Committee for Intractable Diseases of the Ministry of Health and welfare of Japan, and 66 conservatively treated patients with ulcerative colitis, of whom 6 had intractable disease. All patients with major steroid side effects and 17/24 (71%) patients with minor side effects underwent surgery. The median number of admissions was higher in patients with major side effects than in those with less severe or no side effects in the operative series, while this value was lower in the non-operative series than in the operative series. This tendency was similar for the total duration of hospitalization and the number of relapses. In the operative series, markedly higher steroid doses were administered to patients with side effects than to those without, and lower doses were given in the non-operative series. On multivariate regression analysis, the presence of steroid side effects, disease extent, and disease duration were significantly associated with surgery. Patients without side effects had a higher postoperative complication rate than those with minor side effects. We conclude that major side effects are a surgical indication for patients with intractable ulcerative colitis, and that even minor side effects should be taken as a surgical indication in view of the patient's quality of life.