A retrospective analysis was performed in 30 patients who underwent computer-assisted stereotactic resection of intra-axial mass lesions with intractable partial epilepsy. Mean follow-up was 4.1 years (2-5.5), mean age 21 years (3-45) and mean duration of seizures 8.4 years (1-26). Pathology consisted of vascular malformations in 11, glial neoplasms in 11, cortical dysplasia in 4 and gliosis in 3, and no diagnostic abnormality was found in 2 patients. The location of the lesions in some cases may have precluded a standard craniotomy and cortical resection, e.g. precentral gyrus (5), post-central gyrus (5) and deep-seated left posterior temporal region (4). Operative morbidity involved 3 patients who developed motor or language deficits. Four patients were lost to follow-up. Thirteen patients out of 26 (50%) were class I, 3 (12%) were class II, 4 (15%) were class III and 6 (23%) were class IV. These findings suggest that stereotactic lesion resection in selected cases (e.g. where lesions are located in eloquent brain regions) can be useful in providing a histological diagnosis of the epileptogenic foci and result in a favorable reduction in seizure activity without the need for a standard cortical resection.