This study compares outpatient endometrial sampling using the Pipelle endometrial sampling curette with conventional dilation and curettage (D&C) in patients with abnormal uterine bleeding. Endometrial sampling with the Pipelle curette was performed in 172 and D&C in 97 women. No complications were encountered with either of these procedures. One hundred and seventy (98.8%) of the Pipelle aspirations attempted were successfully completed. Sufficient material for histological assessment was obtained in 154 (90.6%) of the women who underwent Pipelle endometrial sampling and in only 66 (68%) of those who underwent D&C (p < 0.0001). In postmenopausal women, adequate specimens were obtained in 74 of 88 (84.1 %) by Pipelle and in only 22 of 48 (45.8%) by D&C. In 45 cases the histologic diagnosis of the endometrium obtained by Pipelle sampling was compared with the one of endometrium obtained by D&C or hysterectomy performed shortly thereafter. The diagnosis was identical in 43 (95.5%) cases. Endometrial sampling with the Pipelle was well tolerated causing occasionally only slight discomfort.