"Purpose: Chronic prostatitis frequently occurs in men of all ages. Recent studies suggest that fastidious microorganisms may play a role in chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). The aim of this study was to investigate if correlation exists between genitourinary Mycoplasmas and Chlamydia infections and CP/CPPS. Materials and Methods: We evaluated Mycoplasmas and Chlamydia prostatitis in 222 patients diagnosed with CP/CPPS from November 2008 to January 2011 by using the Chlamydia and Mycoplasma IST2 kits. Results: Of the 222 patients, 33 (14.9%) and 189 (85.1%) were respectively classified category IIIa (inflammatory CP/CPPS) and IIIb (non-inflammatory CP/CPPS). On kit tests, 10 (30.3%) of the 33 category IIIa and 55 (29.1%) of the 189 category IIIb cases were positive for causative microorganism. Conclusions: The results suggest close correlation between genitourinary Mycoplasmas and Chlamydia infections and CP/CPPS. In addition, the Chlamydia and Mycoplasma IST2 kits may be useful for simple detection of fastidious microorganisms in CP/CPPS."