Since 2004, availability of resources for preventing sexually transmitted diseases in Korean female sex workers (FSWs) has decreased because of strict application of a law against prostitution. This study is to evaluate the condom use and prevalence of Chlamydia trachomatis among FSWs in Korea.

We performed a cross-sectional study of FSWs from 15 major sex work sites in Korea from June to November 2008, using convenience sampling. Self-administered questionnaires and urine samples were collected after all participants' written informed consent. Urine samples were analyzed with PCR at a single central laboratory.

Among 1,086 FSWs who consented to study participation, data from 999 FSWs were appropriate for analysis. C. trachomatis prevalence was 12.8% (95% CI: 10.7-14.9%). Younger age increased risk for C. trachomatis. Whereas majority of FSWs (71.0%) answered high self confidence in condom negotiation, the proportion of FSWs who always used condoms last month was only 23.7%. However, practicing regular condom use showed significant protection against chlamydia infection, not self confidence in condom negotiation.

In Korea, FSWs were not practicing enough self-protection at work with a high prevalence of C. trachomatis. Education for constant practice of protection against sexually transmitted diseases is needed, especially for younger FSWs.