Introduction: This article reviews the rationale and data supporting alpha blocker therapy for chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS), the most common and difficult prostatitis syndrome. Methods: Systematic review identified ten clinical trials evaluating alpha blocker therapy for patients with CP/CPPS, including five open-label or small prospective studies and five double-blinded and placebo-controlled clinical trials. Results: Encouraging results in uncontrolled and small clinical trials led to the development of reasonably powered, double-blinded, placebo-controlled, randomized clinical trials evaluating terazosin, doxazosin, tamsulosin, and alfuzosin. Conclusions: Current data suggest that treatment-naïve and/or newly diagnosed patients appear more likely to respond than long-term, chronic refractory patients. Longer courses of treatment (12 weeks to 6 months) appear superior to shorter courses, and less selective agents appear superior to more selective alpha1 blockers. These observations outline important questions that must be answered to define optimal treatment strategies for patients with CP/CPPS.