Chlamydia trachomatis (CT) is the causative infectious agent for a variety of diseases in men: urethritis, proctitis, conjunctivitis, epididymitis and Reiter’s Syndrome. Among women, the consequences of chlamydial infections are severe if left untreated. Since approximately half of these infections are asymptomatic, many cases go undetected and untreated, leading to additional problems, particularly with pregnant women. In addition, re-infections are frequent if the sex partners are not treated. CT infection can cause urethritis, cervicitis, proctitis, conjunctivitis, endometritis, salpingitis (with subsequent infertility or ectopic pregnancy) and perihepatitis. Infants from infected mothers can develop conjunctivitis, pharyngitis and pneumonia.