BACKGROUND: The clinical presentation of microscopic colitis (MC) consists of chronic non-bloody watery diarrhea for weeks or months at a time, abdominal pain, and changes in bowel habits with a normal mucosal appearance upon performing colonoscopy. MC includes two relatively well established histopathologic entities: collagenous colitis (CC) and lymphocytic colitis (LC) as well as atypical forms. The recognition of the microscopic findings of this heterogeneous entity is very important for making the correct diagnosis and providing proper treatment. METHODS: We studied the colonoscopic biopsy specimens that were obtained from 26 patients who had clinical findings that were suggestive of MC. RESULTS: Fifteen patients (M:F=9:6) and 9 patients (M:F=5:4) showed the microscopic features of LC and MC, not otherwise specified, respectively. CONCLUSIONS: The clinicopathologic findings (the incidence of the subtypes, the patients' ages and the male/female ratio) of the 24 cases of MC in this study showed differences from the previously reported findings from other countries. Further studies with a sufficient number of patients from multi-centers would be necessary to confirm the regional or ethnic influence.