Forty patients with metastatic brain tumors from primary lung cancer underwent radiosurgery (gamma-knife). We retrospectively compared their prior treatment history number of metastatic foci, and performance status, to evaluate the effects of, and indications for, gamma-knife therapy. After both the primary and the metastatic tumors were controlled, performance status could be used as an index in the choice of gamma-knife therapy. Our results demonstrate that repeated gamma-knife radiosurgeries prolonged survival time. Gamma-knife radiosurgery improves quality of life and prognosis of patients with metastatic brain tumors.