The treatment results in 59 patients with extradural spinal cord compression (ESCC) who were treated with irradiation between April 1987 and December 1988 were analyzed prospectively. Eighty percent of the patients presented with back pain, which preceded ESCC by an average of 6 weeks. The most common primary tumor was lung cancer (27% of cases), followed by prostate cancer and breast cancer. The prognostic significance of pretreatment motor function, degree of spinal cord block, radiosensitivity of tumor, and radiation dose schedule was determined with multivariate analysis. Only pretreatment motor function was found to be a significant factor in determining functional prognosis (P = .0058). Even with the increasing clinical awareness of ESCC, 78% of the patients in the current series were nonambulatory at presentation. Therefore, computed tomographic myelography or magnetic resonance imaging is recommended for patients with back pain and bone destruction at the site of the complaint if local radiation treatment is not planned.