The purpose of this Phase II pilot study was to determine whether a dose-intensive regimen of weekly cisplatin combined with other active non-cross-resistant agents would improve the response rate and survival time of patients with extensive non-small cell lung cancer. Patients received cisplatin (50 mg/m2/wk) on days 1, 8, 15, 22, 36, 43, 50, and 57 combined with mitomycin C (8 mg/m2) on days 1 and 36, vinblastine (3 mg/m2) on days 8 and 43, and 5-fluorouracil (5-FU) (1 g/m2) by continuous infusion over 24 hours on days 15 and 50. Responding patients received consolidation therapy with cisplatin and etoposide (VP-16). Of 82 registered patients, 80 were eligible and 77 were evaluable for response. The overall response rate was 23% with 1 patient achieving a complete response (CR) and 17 patients achieving a partial response (PR). The median survival time was 4.6 months. The toxicity profile was not different from that described for standard-dose regimens. Although this regimen does not offer any benefit over standard-dose cisplatin regimens for patients with extensive non-small lung cancer, the weekly schedule permits a dose-intensive regimen with acceptable toxicity for tumors that may benefit from this approach.