T. vaginalis and chlamydia are the most prevalent infectious agents associated with prostatitis. PCR has recently emerged as a powerful tool for T. vaginalis diagnosis with high sensitivity and specificity. This study was done for 120 patients with chronic prostatitis. The "symptom scale score" was used to determine the severity. T. vaginalis infection was diagnosed in 6 out of 120 patients. There is a significant direct relation comparing between the severity of the symptoms and the detection of T. vaginalis (The p value is 0.001). All of the diagnosed patients with T. vaginalis were also infertile.