Although the evolution from low-dose rate (LDR) to high-dose rate (HDR) brachytherapy for malignant endobronchial tumors was presumably based on economy, patient convenience, and radiation protection, our experience with both modalities permits assessment of the pros and cons of each technique. In November 1991, our HDR remote afterloading brachytherapy unit became operational. By that time, we had treated 110 patients (group 1) with malignant endobronchial obstruction with LDR brachytherapy. Since then, all patients have been treated with HDR brachytherapy. The outcome of our first 110 patients (group 2) treated with HDR brachytherapy is presented in this communication, using group 1 as the historic control group. In group 1, patients were treated with 1 or 2 sessions of 30-60 Gy, each calculated at a 1-cm radius. In group 2, patients received 3 or 4 weekly treatments of 7 Gy, each calculated at a 1-cm radius. The majority of patients in each group had previously received a full course of external beam irradiation, and a history of laser bronchoscopy was also similar for the 2 groups. Differences in bronchoscopic response rate (82% vs. 96%, respectively) and complications (3.6% vs. 2.7%, respectively) were statistically insignificant between the LDR group and the HDR group. We believe HDR brachytherapy is the state-of-the-art modality in intraluminal therapy for endobronchial malignancies.