BACKGROUND: Oculomotor nerve palsy (OMNP) is a known risk in surgical management of intracranial aneu-rysms. The aim of this study was to determine the risk factors for surgery-induced OMNP.METHODS: This retrospective study examined 585 pa-tients with posterior communicating artery aneurysms treated surgically between January 2000 and July 2019. The patients were categorized into 2 groups according to whether they experienced OMNP. Multiple factors, including sex, age, history of subarachnoid hemorrhage, Hunt and Hess grade, Fisher grade, preoperative time, sizes, sides, number, orientation, intraoperative rupture, and morphology, were analyzed to identify factors associ-ated with surgery-induced OMNP. RESULTS: The overall OMNP rate was 4.4%. In univari-ate analysis, large size (P < 0.001), posterior infratentorial projection (P = 0.003), number of subarachnoid hemor-rhages (P = 0.005), and late preoperative time (P < 0.001) were associated with increased risk of OMNP. Overall, multivariate logistic regression analysis showed that size (10.1-25 mm: odds ratio [OR] 30.083, P = 0.001, 95% con-fidence interval [CI], 3.703-244.419; >25 mm: OR 62.179, P = 0.012, 95% CI, 2.402-1609.418), intraoperative rupture (OR 3.018, P = 0.035, 95% CI, 1.083-8.412), and preoperative time (>14 days: OR 10.985, P < 0.001, 95% CI, 3.840-31.428) were independent risk factors of surgery-induced OMNP.CONCLUSIONS: This study showed that size, intra-operative rupture, and preoperative time were independent predictors of surgery-induced OMNP. Use of advanced technologies during the operation can assist in avoiding this complication.