This study was conducted to assess the efficacy of systemic chemotherapy in patients with brain metastasis from non-small cell lung cancer. Sixty-three consecutive patients who were diagnosed as having non-small cell lung cancer (NSCLC) with synchronous brain metastasis (BM) and had not been previously treated were included in this study. After cranial radiation therapy (RT), all patients in 'the chemotherapy arm' (CTX) were treated with platinum-based combination chemotherapy, and best supportive care was selected for patients in 'the no-chemotherapy arm' (no-CTX). Thirty-one of the 63 patients received systemic chemotherapy. The median age of all patients was 55 years. The performance status of all patients was ECOG grade 1-2. Twenty-two patients had a solitary brain metastasis, 37 patients had more than two masses, and 38 patients had extracranial metastatic lesions. In the CTX arm, a paclitaxel-based combination chemotherapy was administered in 38.7%, gemcitabine-based in 25.8%, and vinorelbine-based in 25.8% as the first-line chemotherapy. Seventeen patients were treated with a second-line chemotherapy, and paclitaxel plus gemcitabine was used in 8 patients. For the first-line and second-line chemotherapies, extracranial overall responses were 36 and 35%, the median response durations were 29.1 weeks (range: 9.1-58.1 weeks) and 30.4 weeks (range: 19.4-44.0 weeks), respectively. 'Progression of the extracranial lesion' (58.1%) was more frequent than an 'aggravation of neurologic status' (19.4%) for the pattern of treatment failure in the first-line chemotherapy. The causes of failure were identical in the second-line chemotherapy. The median survival of the CTX arm was longer than that of the no-CTX arm (58.1 vs. 19.0 weeks, p<0.001). Toxicity in the CTX arm was tolerable. The systemic chemotherapy showed an effectiveness to increase the survival of patients with BM from NSCLC, and extracranial progression was the main cause of chemotherapeutic failure, although consideration for non-randomized methods should be made in this study.