The objective of the study was to determine the incidence and type of endometrial abnormalities in long-term users of tamoxifen with breast cancer. All patients with a diagnosis of Oestrogen Receptor positive breast cancer on Tamoxifen therapy who had also undergone endometrial biopsy for abnormal bleeding or other symptoms were included. Among the 37 cases that had long-term follow up available, 21(57%) had evidence of endometrial pathology. There were seven cases of simple hyperplasia and thirteen of endometrial polyp. Only one case of endometrial carcinoma was seen. These findings support the association between prolonged tamoxifen therapy and endometrial pathology of possible neoplastic potential. Endometrial pathology is dependent on duration of exposure to Tamoxifen, therefore, close follow up of such patients is recommended.