Ablation of the endometrium is now an established treatment modality for dysfunctional uterine bleeding (DUB). There have been few reports of the inflammatory and healing reaction within the endomyometrium subsequent to this therapy, and its identifying characteristics. The morphologic reaction after electrosurgical ablation in particular has received scant attention. In this retrospective study, 19 women were identified who had undergone both an endometrial ablation using electrosurgical rollerball ablation and a subsequent endometrial sampling or hysterectomy. The average age of the patients was 47 years (range, 28 to 60). Fifteen patients had been ablated for DUB, while four had been ablated immediately after a resection that later revealed atypical hyperplasia. Histopathologic specimens were examined from 1 to 48 months postablation. The six specimens examined at 3 months or less after ablation all exhibited necrotic myometrium, and in five of these six cases, a florid foreign body and granulomatous reaction to necrotic myometrium and spicules of thermally damaged myometrium. A variable degree of acute inflammation was evident in all six cases and was exclusively present in one case. The remaining 13 cases were examined at > 3 months posttreatment. Necrotic myometrium was no longer evident, but a persistent granulomatous, a foreign-body reaction, or both was detected in 5 of 12 cases up to 16 months postablation. In most cases (9 of 12), there was striking endometrial scarring. The morphologic response of the endometrium after electrosurgical endometrial ablation is similar to that reported previously for both resection and laser ablation. Post-hysteroscopic ablative reaction should be recognized and distinguished from other causes of granulomatous endometritis.