The presence of brain metastasis in lung cancer patients is a highly unfavorable event that usually allows only palliative treatment. A retrospective study was conducted to evaluate the prognostic factors in patients with non-small cell lung cancer (NSCLC) associated with brain metastases. From July 1984 through June 1990, a total of 50 patients with NSCLC associated with symptomatic brain metastasis seen at National Taiwan University Hospital were included. Patients who had incomplete cancer staging workup or loss of follow-up were excluded. Several possible prognostic variables were analyzed initially with univariate analysis and subsequently with multivariate analysis with maximal partial likelihood ratio test in the Cox model. In the univariate analysis, several factors, including number of brain metastases, treatment for brain metastasis with brain tumor resection (BTR) or whole brain radiation therapy (WBRT), and chemotherapy (C/T) after brain metastasis were found to have significant influence on the survival. However, in the multivariate analysis, patients receiving BTR, WBRT, and/or C/T lived significantly longer. The median survival of patients treated with BTR was nine months, eight months in patients with C/T, and seven months in patients with WBRT. Taken together, these patients had a median survival of seven months, which was significantly longer than patients treated with supportive care only (with a median survival of two months). Treatment of brain metastases with WBRT, BTR, C/T, or in combinations also improved the quality of life. We conclude that NSCLC patients with brain metastases should be more aggressively treated with WBRT, BTR, C/T, or in combinations than supportive care only.