OBJECTIVE To evaluate the therapeutic outcomes and late toxicities in patients treated by high-dose-rate brachytherapy (HDR-BT) with external beam radiotherapy (EBRT) for localized or locally advanced prostate cancer. METHODS From May 2004 to September 2008, 86 men were treated by HDR-BT with EBRT for localized or locally advanced prostate cancer at the National Hospital Organization Kyushu Medical center. The median EBRT and HDR-BT doses were 40 Gy and 30 Gy, respectively. RESULTS With a median follow-up of 24 months, the 3-year overall, disease specific, and biochemical relapse-free survival rates in all patients were 97.3%, 100%, and 83.6% respectively. The 3-year biochemical relapse-free survival rate of the patients categorized to low or intermediate risk group (91.8%) was significantly better than that of the patients categorized to the high risk group (74.3%) (p = 0.042). There was no significant difference of biochemical relapse-free survival regarding to the other clinical factors (age, T-stage, Gleason score, initial prostate-specific antigen level, neoadjuvant hormone therapy, and total dose of EBRT and HDR-BT). Late Grade2 and Grade3 gastrointestinal toxicities were observed in 8 patients (9.3%) and 2 patients (2.3%), respectively. Late Grade2 genitourinary toxicities were observed in 12 patients (13.9%). There was no patient suffered from late Grade3 or greater genitourinary toxicities. CONCLUSIONS HDR-BT with EBRT can be safe and effective for localized or locally advanced prostate cancer.