Objective. To determine the incidence and significance of recurrent postmenopausal bleeding among women diagnosed with an endometrial thickness <= 4 mm after a first episode of postmenopausal bleeding. Methods. Consecutive patients not using hormone replacement therapy (HRT) presenting with a first episode of postmenopausal bleeding and an endometrial thickness <= 4 mm at transvaginal ultrasonography (TVU) were managed expectantly. In case of recurrent bleeding, the patient was evaluated according to the hospital's local policy with TVU, office endometrial sampling, hysteroscopy or dilatation and curettage (DC) or a combination of these tests. We evaluated the incidence of recurrent bleeding, potential risk factors for recurrent bleeding, and the diagnosis made after recurrent bleeding. Results. A total of 607 patients were registered with a first episode of postmenopausal bleeding, of whom 249 had an endometrial thickness <= 4 mm. Follow-up took place with a median of 174 weeks (range: 4-250 weeks). During follow-up, 25 of the 249 patients (10%; 95% CI: 6.6-14%) had recurrent bleeding. Median time until recurrence of bleeding was 49 weeks (range: 9-186 weeks). Two patients with recurrent bleeding turned out to have an endometrial carcinoma (8%; 95% CI: 2.2-25%), and 1 patient had a malignant melanoma. Time since menopause, age, body mass index, hypertension, diabetes and anticoagulants were not predictive for recurrent bleeding. Conclusion. The recurrence rate after a first episode of postmenopausal bleeding managed expectantly is low and cannot be predicted by patient characteristics. Patients with recurrent bleeding should be re-evaluated, as they bear a considerable risk of carcinoma.