Chlamydia trachomatis is one of the most common sexually transmitted human pathogens. Chlamydial infection is a problem concerning about 12% of young, sexually active persons at reproductive age. Because of subtle or, particularly at women, asymptomatic course, the disease may be imperceptible by patients and untreated until complications occur. When the infection spreads outside cervix and urethra,W irreversible damages in the range of genital-urinary system are often. Fever and leucocytosis can confirm the complications, occurring in the form of pelvic inflammatory disease, causing infertility. Health education, screening programs for high risk patients and proper early treatment of both sexual partners could contribute to decreasing dangerous results of chlamydial infections, especially in aspect of marital infertility problem.