INTRODUCTION: There is debate regarding the risks and benefits of prophylactic oophorectomy at the time of hysterectomy for benign indications. The purpose of this study was to examine hospital variation in this practice. METHODS: Using data from the 2012 National Inpatient Sample, we identified 51,540 hospitalizations for benign, nonobstetric hysterectomy among adult patients based on International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis and procedure codes. Prophylactic oophorectomy (defined as bilateral oophorectomy, bilateral salpingo-oophorectomy, or removal of remaining ovary) was identified using ICD-9 CM procedure codes. We used a hierarchical generalized linear model to risk-adjust for patient age and comorbidities and calculated for each hospital the ratio of predicted-to-expected prophylactic oophorectomy. A ratio greater (less) than one suggests that more (fewer) prophylactic oophorectomies were performed than expected. All analyses accounted for National Inpatient Sample weights. RESULTS: Among 702 hospitals nationwide that had at least 25 benign hysterectomies sampled, unadjusted rates of prophylactic oophorectomy varied markedly from 5.1% to 92.0% (mean 40.5%, median 39.4%). After risk adjustment for patient clinical characteristics, the ratio of predicted-to-expected prophylactic oophorectomy ranged from 0.18 to 3.28 (mean 1.01, median 0.98). Rural hospitals had higher predicted-to-expected ratios than urban teaching or nonteaching hospitals (P<.01). There is also a significant difference in the predicted-to-expected ratio of prophylactic oophorectomy by region (higher in the Midwest and South, whereas lower in the Northeast and West) (P<.01). CONCLUSION AND IMPLICATION: Hospitals vary widely in their practice of prophylactic oophorectomy with significant differences by geographic and urban or rural location. These results highlight the need for better guided clinical care and identification of other influencing factors for the variation.