The objective of this study was to evaluate whether extracorporeal magnetic innervation (ExMI) combined with a-blocker therapy is more effective than a-blocker monotherapy for patients with non-inflammatory chronic prostatitis (CP)/chronic pelvic pain syndrome (CPPS), category IIIB. Patients were randomized to either terazosin monotherapy (group 1, n ¼ 21) or terazosin combined with ExMI therapy (group 2, n ¼ 19). Patients in group 2 had 12 treatment sessions of ExMI twice a week during 6 weeks. None of the patients experienced any side effects from treatment. The changes in each domain of the National Institutes of Health (NIH)-Chronic Prostatitis Symptom Index (CPSI) measured on week 6 were not significantly different between the groups. However, the difference (median, 25-75th percentiles) between the two groups in total NIH-CPSI scores was À4 (À11.5, À2) for group 1 and À12 (À17.3, À2.3) for group 2, respectively (P ¼ 0.047). At 6 weeks, 47.6% (10 of 21) of group 1 had a 425% decrease in total NIH-CPSI compared with 78.9% (15 of 19) of group 2 (P ¼ 0.041). Also, more patients in group 2 (78.9%) were rated as responders with a 6-point decrease in NIH-CPSI compared with group 1 (47.6%) (P ¼ 0.041). The early results suggest that ExMI combined with a-blocker therapy has better effect than a-blocker monotherapy for the treatment of CP/CPPS.