Bronchial angiography was performed in 9 patients with squamous cell carcinoma of the lung. The tumour-feeding vessel was identified and infused with 10 mg of mitomycin-C (MMC) diluted in saline. At operation after 28 to 48 days complete remission of the tumour had occurred in 2 patients, almost complete in one, partial remission in 2 and a marked regression in 2. In 2 patients no change was noted. No side effects except moderate malaise and slight fever occurred.