Axial computed tomographic scans were used to guide percutaneous needle biopsies in 76 patients with thoracic and lumbar spinal lesions. Prebiopsy evaluation included spine radiographs, radionuclide bone scans, computed tomographic scans, magnetic resonance imaging scans in some cases, and coagulation studies. Forty-five patients were diagnosed as having metastatic lesions, 11 infection, and 12 primary bone tumors. Of all patients, 34 had lytic vertebral lesions with significant collapse and questionable spinal stability. Six of those had a concomitant paravertebral mass. A clinical and pathologic correlation was completed for each of the cases studied. Histologic diagnosis confirming the clinical suspicion was obtained on the first biopsy attempt in 65 (86%) of the 76 cases.