Fifteen patients (six patients with adenocarcinoma, seven patients with squamous cell carcinoma, and two patients with large cell carcinoma) with advanced non-small cell lung cancer (NSCLC) were evaluable for mitomycin C (MMC; 8 mg/m2 day 1, 8, every 3-4 weeks) plus cisplatin (CDDP; 80 mg/m2 day 1, every 3-4 weeks). Ten patients had had prior chemotherapy. Among 15 evaluable patients, no patient achieved complete response, and two patients showed partial response. The response rate of MMC plus CDDP against NSCLC was 13.3%. Toxic effects included anorexia (80%), nausea and vomiting (67%), leukopenia (53%), anemia (47%), nephrotoxicity (47%), thrombopenia (27%), liver injury (27%), and fever (7%). These toxic effects were reversible and manageable. The combination of MMC and CDDP appears to be valuable regimen against advanced NSCLC.