Objective: To evaluate the long-term outcomes of subtotal hemispherotomy (SH) in treating drug-resistant epilepsy caused by unilateral hemispheric lesions and try to give the prognostic factors for these outcomes., Methods: We retrospectively reviewed the clinical data of 19 patients who underwent SH in Sanbo Brain Hospital, Capital Medical University, Beijing, China, from May 2008 to April 2021. All clinical data and factors related to surgical and functional outcomes, including motor, neuropsychiatric, and language function, were collected and analyzed., Results: The surgical outcomes showed 13 (68 %) patients were seizure-free at the last follow-up (2-14 years, mean: 5.6±2.9). No changes were found in motor outcomes in 12 (63 %) patients; seven (37 %) patients had new permanent motor deficits (NPMD). Improvement in the full-scale intelligence quotient (FIQ) (p = 0.009) was observed. Univariate analysis found that patients who did not achieve seizure freedom had a significantly older age at surgery (p = 0.017) and acute post-operative seizures (APOS) (p = 0.046). Kaplan-Meier analysis also identified significant differences in seizure outcomes between the children and adult subgroups (p = 0.0017). Multivariate Cox analysis showed that older age at surgery (HR=1.055, p = 0.034) was associated with shorter time-to-seizure-recurrence. Resection of the central operculum and insula (OR= 80.433, p =0.031) and higher monthly seizure frequency (OR= 1.073, p = 0.040) were also poor prognostic factors for motor function outcomes., Conclusion: SH is an effective treatment procedure in treating patients with drug-resistant epilepsy caused by hemispheric lesions with satisfied seizure outcomes, limited impairment of motor function, and preserving neuropsychiatric outcomes., Competing Interests: Declaration of Competing Interest None of the authors has any conflict of interest to disclose., (Copyright © 2024 Elsevier B.V. All rights reserved.)