Twenty-five patients receiving surgical treatment for brain metastasis from lung cancer were retrospectively studied to evaluate the prognostic factors for survival time. Twenty-two patients had died of respiratory distress by April, 1989. Favorable prognostic factors derived from the median survival time (MST) in these patients included; 1) resection of primary tumor (MST 10 months); 2) total or subtotal removal of metastatic tumor (MST 6.5 months); 3) adenocarcinoma (MST 13 months); 4) metachronous onset of brain metastasis (MST 12 months); 5) single metastasis (MST 8 months). These results suggest that therapy for the primary lung cancer is important before surgery for metastatic brain tumor.