Between September 1990 and September 1991, 35 patients with mainly recurrent or residual endobronchial carcinoma were treated with 91 high-dose-rate endobronchial brachytherapy applications. Treatment technique was fairly simple and could easily be performed on an outpatient basis. Endoscopic placement of one or two applicators is followed by computerized dosimetry and irradiation during a median time of 10 minutes. Treatment included 3 sessions of 10 grays measured at 10 mm from the center of the radioactive source at 2-week intervals. Response rate was 81.8% including 51.5% complete clinical response. There were 12 microscopically complete response out of 14 patients biopsied. Immediate tolerance was excellent in 90% of cases. However, late complications were severe in 25% of cases. Ongoing radiobiological research should determine an optimal therapeutic approach in term of efficacy and long term toxicity before using endobronchial brachytherapy as a part of the initial management of unresectable lung cancers.