Between 1985 and 2001, seven Japanese patients (four males and three females) were diagnosed as having primary sclerosing cholangitis (PSC) in our hospital. All seven patients received total colonoscopy with distal ileoscopy. All four male patients were diagnosed as having colitis by colonoscopy, while none of the three female patients had colitis. The four patients with colitis did not have any symptoms attributable to colitis, such as diarrhea or hematochezia. In three of the four patients, unclassified colitis was the most suitable diagnosis, because there were no typical findings of ulcerative colitis or Crohn's disease. The remaining patient was diagnosed as having eosinophilic colitis. By colonoscopic visualization, the right-sided colon, including the terminal ileum, was mainly involved, but the lesions were not severe. The main findings were redness, erosion, stenosis, and insufficiency of haustral formation. Histologically, these lesions were nonspecific inflammatory changes in the three patients with unclassified colitis. In the patient with eosinophilic colitis, remarkable infiltration of eosinophils was observed. Thus, unclassified colitis appeared to be the main complication in these patients with PSC. Males predominated in regard to concomitant colitis, and they had no symptoms of the colitis. Colonoscopic examination revealed that the lesions were not severe. The main lesions were found in the right-sided colon, with nonspecific inflammatory changes. These results suggest that colonoscopic surveillance of patients with PSC should be performed even if they do not have any colitis symptoms.