Non-small cell lung cancers (NSCLCs) are among the most common malignancies. Although pemetrexed is often used clinically to cure cancers, its efficacy in NSCLC patients with progressive brain metastases remains unclear. Here, we report a successful NSCLC (adenocarcinoma) case treated with pemetrexed. The detected tumors were treated with 900 mg of pemetrexed disodium (500 mg/m(2)) was administered to the patient on day 1, and 40 mg of cisplatin (25mg/m(2)) was administered on days 1-3, at the interval of 3 weeks. After two cycles of chemotherapy, the brain metastases were reduced. The lesion in the lung was reduced as determined by chest CT-scan. Our results suggest that pemetrexed is an effective therapy for patients with NSCLC and progressive brain metastases.