OBJECTIVE We assessed rates of oophorectomy during benign hysterectomy around the release of the American College of Obstetricians and Gynecologists 2008 practice bulletin on prophylactic oophorectomy, and evaluated predictors of inappropriate premenopausal oophorectomy. METHODS A cross-sectional administrative database analysis was performed utilizing the California Office of Statewide Health Planning Development Patient Discharge Database for years 2005 to 2011. After identifying all premenopausal women undergoing hysterectomy for benign conditions, International Classification of Diseases (ICD)-9 diagnosis codes were reviewed to create a master list of indications for oophorectomy. We defined appropriate oophorectomy as cases with concomitant coding for ovarian cyst, breast cancer susceptibility gene carrier status, and other diagnoses. Using patient demographics and hospital characteristics to predict inappropriate oophorectomy, a logistic regression model was created. RESULTS We identified 57,776 benign premenopausal hysterectomies with oophorectomies during the period studied. Of the premenopausal oophorectomies, 37.7% (21,783) were deemed "inappropriate" with no documented reason for removal. The total number of premenopausal inpatient hysterectomies with oophorectomy decreased yearly (12,227/y in 2005 to 5,930/y in 2011). However, the percentage of inappropriate oophorectomies remained stable. In multivariate analysis, Hispanic and African American ethnicity/race associated with increased odds of inappropriate oophorectomy (P < 0.001). Urban and at low Medi-Cal utilization hospitals showed increased odds of inappropriate oophorectomy. CONCLUSIONS In premenopausal women undergoing benign hysterectomy, over one-third undergo oophorectomy without an appropriate indication documented. The rate of inappropriate oophorectomy in California has not changed since the 2008 American College of Obstetricians and Gynecologists guidelines. Whereas the absolute number of inpatient hysterectomies for benign indications has decreased, our work suggests persistent utilization of oophorectomy in premenopausal women, despite well-documented long-term adverse health implications.