Cisplatin-containing regimens have shown activity in both small and non-small cell lung cancer. We therefore conducted a randomized Phase II trial of the new platinum congeners iproplatin and carboplatin in bronchogenic carcinoma. The overall response rate in chemotherapy-naive non-small cell patients with iproplatin was 3/48 (6%; 95% confidence interval 2-18%) and with carboplatin 6/50 (12%; 95% confidence interval 5-25%). The response rates in previously treated small cell patients were 0/16 and 1/18, respectively. Overall, neither agent has pronounced activity in bronchogenic carcinoma.