OBJECT Accurate intraoperative localization of small intradural extramedullary thoracolumbar (T-1 to L-3 level) spinal cord tumors is vital when minimally invasive techniques, such as hemilaminectomy, are used to excise these lesions. In this study, the authors describe a simple and effective method of preoperative MRI localization of small intradural extramedullary tumors using cod liver oil capsules. METHODS Thirty-five patients with intradural tumors underwent preoperative MRI localization the evening prior to surgery. Patients were positioned prone in the MRI gantry, mimicking the intraoperative position. Nine capsules were placed in 3 rows to cover the lesion. This localization was used to guide the level for a minimally invasive approach using a hemilaminectomy to excise these tumors. RESULTS The mean patient age was 51.5 ± 14.3 years, and the mean body mass index was 24.1 ± 3.5 kg/m(2). Twenty-two tumors involved the thoracic spine, and 13 involved the upper lumbar spine from L-1 to L-3. The mean tumor size was 2.2 ± 1.0 cm. Localization was accurate in 34 patients (97.1%). CONCLUSIONS Accurate localization with the described method is quick, safe, cost-effective, and noninvasive with no exposure to radiation. It also reduces operating time by eliminating the need for intraoperative fluoroscopy.