Five patients with clinically inoperable bronchial squamous cell carcinoma were treated with infusions of 10 mg Mitomycin-C in the bronchial artery feeding the tumour, in an attempt to make inoperable bronchogenic carcinoma resectable. One patient had only one treatment while the other four had the infusion repeated three times with an interval of two weeks between treatments. In all cases there was a marked regression of the tumour. Four patients had the tumour resected 1-2 weeks following the last treatment and two of these are still alive 2 1/2 and 4 years later. The other two patients died 14 and 22 months following the initiation of the treatment. The fifth patient developed serious adverse effects to the drug that only slowly subsided. He died 5 1/2 months following the initiation of the treatment and his tumour was not resected. This limited study demonstrates the possibility of making certain inoperable patients with bronchogenic carcinoma operable, but it also stresses the problems of a correct preoperative staging.