Objective: To determine endometrial causes of abnormal uterine bleeding. Study design, Setting & Methods: Descriptive study carried out at Gyn/ obs department unit 1V Lyari General Hospital from Jan 2008- Dec 2009. Out of 728 gynae admissions 86 premenopausal women with abnormal uterine bleeding were selected for further workup. premenopausal group include menstrual group (20-40 years) and perimenopausal group (>40 years). After general & local examination & necessary investigations these women underwent hysteroscopic guided endometrial biopsy under anaesthesia. Details of histopathology obtained from laboratory. Results: All admitted premenopausal women with abnormal uterine bleeding were studied. Majority 97.7% was multiparous & menorrhagea was main mode of presentation. Histology of endometrium in menstrual group: normal endometrium 52%, endometritis 26%, endometrial polyp 17.3%, simple hyperplasia 4.3%. In perimenopausal group: normal endometrium 20%, endometritis 50%, cystic hyperplasia 30%. Non had atypical hyperplasia & endometrial cancer. Conclusion: Risk of endometrial hyperplasia is high in perimenopausal women with abnormal uterine bleeding. Endometrial biopsy is recommended in them.