Sixty-six patients with lung cancer were treated with endoscopic laser irradiation. In this study, photodynamic laser therapy (PDT) was performed on 28 patients with early lung cancer and 38 patients with advance lung cancer having 69 biopsy-proven malignant lesions of the trachea and bronchus. The patients were administered HpD (2. 5 mg/kg of their weight) injected intravenously three days prior to HpD-mediated laser phototherapy. These patients have completed at least one course of this therapy which was carried out by flexible bronchofiberscope. The laser beam was delivered through an optical fiber connected to the output of a dye laser (630 +/- 3 nm). The optical fiber was passed through the large inside channel of the flexible bronchofiberscope. Among the 69 malignant lesions of the trachea and bronchus, complete responses were obtained in 9 malignant lesions, partial responses in 44 cases, regressions in 13 cases, and the remaining 3 cases had progressions. Of the 66 patients, 19 patients are alive with no recurrence or metastasis, while the remaining 47 patients died after photodynamic laser therapy. The patients treated with photodynamic laser therapy (PDT) had unresectable lung cancer which was observable by bronchofiberscopy but not suitable for radical treatment either by chemotherapy or radiation therapy. We studied a selection of patients with unresectable lung cancer for application of a treatment combining endoscopic laser irradiation and radiotherapy.