Purpose of investigation: 1) To assess whether endometrial specimens obtained from removed uteri might show an increase in endometrial pathologies which had been previously diagnosed by hysteroscopy in postmenopausal breast cancer tamoxifen-treated patients. 2) To assess whether hysteroscopy is an efficient method of detecting endometrial pathologies in such patients. Methods: The findings of two consecutive pathological evaluations in 18 postmenopausal breast cancer tamoxifen-treated patients, performed 11.2 ± 11.2 months apart, were compared. The first specimen was collected by hysteroscopy and the second was obtained following hysterectomy. Results: The most significant changes observed were three new cancers diagnosed at hysterectomy, one of which was poorly-dif­ferentiated. In the first (hysteroscopy) samplings, one patient had atrophic endometrium, a second patient had endometrial prolife­ration and a third patient had a benign endometrial polyp. Overall, 55.6% of the study patients had various endometrial pathologies in the first sampling, while 83.3% had endometrial pathologies in the second sampling. However, this difference was not statistically significant. Conclusion: 1) Endometrial histologic evaluations, performed on removed uteri 11.2 ± 11.2 months following previous endometrial samplings of postmenopausal breast cancer tamoxifen-treated patients, showed a non-significant risk of developing overall endometrial pathologies. 2) Hysteroscopy may have missed some endometrial pathologies which were diagnosed later on in specimens obtained by hysterectomy.