Sexually transmitted  infection (STIs) are a major global cause of acute lleness,infertility ,long term disability and death with sever medical  psychological consequence for millions of men,women and infants.Meanwhile  Chlamydia trachomatis which is a gram negative bacteria could places a heavy  burden on women and neonatal health,consist  of chronic pelvic pain,  pelvic inflammatory disease ,ectopic pregnancy,infertility , infant pneomonia and neonatal ophtalmia.The world health organization (WHO) estimated that 90 million cases occur annually on a global basis and in young women the proportion infected ranges from 8-40%, with a  median of about 15%. In Iran the information about prevalence of chlamydia  trachomatis is rare, so having more information could help to prepare  complete estatic about situation of infection and also could help to  mother and children healthy. In this study we had 3 groups of women who reffered to gynecologist  for genital problems, D&C or spontanous abortion .with dacron swab ,specimens were gathered and placed in 2sp medium for each paitent and rereservoir in -70c refrigerator for  molecular detection. Consequently with 2 pairs of primers Nested PCR  were done.  Our result revealed that the preavalence  of chlamydiat Trachomatis among 3 groups  in order of was 35%,43%,43.8%,Mean of prevalence between 3 groups was: 40.6% , there is not significant  difference  between 3groups.