The aim of this study is to present our preliminary experience in treating BPH-related urine retention, resistant to other medical treatment, with transurethral brachytherapy. We also deal with dosimetric analysis so as to eliminate ethical concerns about the exposure of patients not suffering from cancer to a certain level of body irradiation. Patients suffering from BPH-related urethral obstruction were treated with two transurethral applications (three weeks apart) of Cs137 MDR, which delivered a total of 16 Gy, at 0.5 cm from the urethral walls (dose rate 5-7 Gy/h). The application was done under ultrasonographic observation. Dosimetric calculation of the radiation exposure of the human body during transurethral radiotherapy (TURT) was performed for patients suffering from prostate cancer and treated with external beam radiotherapy and a boost dose through transurethral brachytherapy. For this purpose we used TLDs on skin surface and dosimetric analysis of X-ray films. Five patients treated for BPH urethral obstruction presented no sign of acute toxicity. All of them were weaned of their indwelling catheter immediately after the end of the first application. Obstruction did not recur within 12-18 months of follow-up. The dose delivered outside the prostate ranges from 1-7 cG, depending upon location. Proximal rectal and bladder walls received 1-2 Gy, a dose that is far from inducing acute or late toxicity. The estimated risk for carcinogenesis is negligible, and the expected benefit for the quality of life transcends the risks. No ethical concern is justified for testing transurethral radiotherapy for BPH-related urethral obstruction. TURT seems to be effective and provides durable results. Further investigation is required.