The histopathologic study of the curettaged endometrial tissue taken from the patient with the clinical impression of dysfunctional uterine bleeding was performed. The total 221 cases of this study were classified as 76 cases of proliferative phase, 46 cases of secretory phase, 25 cases of menstrual phase, 25 cases of hyperplasia, 18 cases of chronic inflammation, 11 cases of irregular shedding, etc. Even age distributions were present in the patient of proliferative, secretory and menstrual phases. However, most cases of hyperplasia, irregular shedding, atrophy and adenocarcinoma of the endometrium were found at the age of more than 40. The metaplastic changes of endometrial tissue were present in about 1/3 of total cases. Almost all of these metaplastic changes were epithelial metaplasia. The most common type of epithelial metaplasia was tubal metaplasia which was observed mostly in the hyperplasia including cystic and adenomatous hyperplasia. The varieties of metaplastic changes occurred in the proliferative phase, secretory phase, chronic endometritis and menstrual phase in order. There were only 2 cases of mesenchymal metaplasia which was osseous and smooth muscle metaplasia.