Summary Chlamydia trachomatis is an important bacterial cause of infertility. In men, the recommended specimen for diagnosing chlamydial infection is urine, with little or no emphasis placed on testing semen. A systematic review of the literature was conducted to search for studies in which men undergoing investigations for infertility produced both samples of urine and semen that were tested concurrently for C. trachomatis. An analysis of these studies was then performed. From 322 papers identified from the US National Library of Medicine PubMed database, 14 were selected for a detailed review and 11 were analysed further. Overall, the size of the study groups was only modest and differences between the studies included variation in geography and test methodology, especially whether commercial testing systems had been used. There was also a lack of consistency with regard to including men with azoospermia. Patients were typically 30-35 years old and the median duration of infertility was about 4 years. Of those patients positive for C. trachomatis in the 11 studies, 56% could be detected in both semen and urine, 20% only in urine and 23% only in semen. Deficiencies in existing studies would not allow for a meta-analysis, emphasizing the need for further research in this area for which a number of recommendations are made. [ABSTRACT FROM AUTHOR]