Introduction. Chlamydia trachomatis is an established cause of tubal factor infertility; however its role in male fertility is not as clear. We sought to determine the prevalence of Chlamydia in infertile men and evaluate its impact on male reproductive potential. Materials and Methods. We compared the incidence of Chlamydia in our infertile male population with that reported in the literature. We then reviewed the impact of Chlamydia infection on male fertility. Results. The incidence of Chlamydia infection in our population of infertile men was 0.3%. There is considerable variability in the reported incidence, likely due to variation in the population studied, and detection technique. The optimal testing method and sample are presently unclear. The effect of Chlamydia on male reproductive function is also variable in the literature, but appears to be relatively minimal and may be related primarily to sperm DNA fragmentation or female partner transmission. Conclusions. The prevalence of Chlamydia in the infertile male population is low and routine testing is not supported by the literature. For high-risk infertile men, nucleic acid testing of urine +/？ semen is the most sensitive method to detect Chlamydia. A validated testing system for semen needs to be developed, so that a standardized methodology can be recommended. In this way the full implications of Chlamydia on male fertility can be elucidated. 1. Introduction Chlamydia trachomatis (C. trachomatis) is the most prevalent sexually transmitted disease in the world and a common cause of pathology in both men and women, causing urethritis, epididymitis, prostatitis, cervicitis, pelvic inflammatory disease (PID), ectopic pregnancy, and tubal factor infertility [1]. While there are regional differences in the prevalence, it remains a common cause of genitourinary pathology in both men and women. In women C. trachomatis is a well-established cause of tubal factor infertility. In men it is a known common genitourinary pathogen, and electron microscopy has clearly demonstrated that C. trachomatis attach to spermatozoa [2–5], both on the surface and in the nucleus [6]; however its role in male fertility (sperm function, pregnancy rates, and live birth rates) is not clear. As the etiology of approximately 55% of male factor infertility is unknown, it is possible that Chlamydia is contributory in some of these cases. In our study in a Canadian clinic, we identified a very low prevalence of Chlamydia in the infertile male population of only 0.3% [7]. This is the largest study of the prevalence of C.
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