eThe prevalence of Mycoplasma genitalium is high in vulnerable populations of women in low-resource settings. However, the epidemiology of infection in these populations is not well established. To determine the prevalence of Mycoplasma genitalium and its association with cervical cytology and other correlates, we recruited 350 female sex workers (FSW) who were 18 to 50 years old in Nairobi, Kenya, for a cross-sectional study. A questionnaire was administered at baseline to obtain information on sociodemographics and sexual behaviors. Women underwent a pelvic exam, during which a physician collected cervical-exfoliation samples for conventional cytology and sexually transmitted infection (STI) testing. Samples were tested for M. genitalium Mycoplasma genitalium is an emergent bacterium that is transmitted via sexual activity and has been associated with complications in the female genital tract, including endometritis, tubal-factor infertility, pelvic inflammatory disease (PID), cervicitis, and ectopic pregnancy (1-9). M. genitalium may also increase the risk of HIV transmission and associated shedding (10-13).Vulnerable populations of women in low-resource settings have a higher-than-average susceptibility to sexually transmitted infections (STIs) and subsequent complications of the reproductive tract, including those caused by M. genitalium, Chlamydia trachomatis, and Neisseria gonorrhoeae (14). In the case of female sex workers (FSWs), STI risk is increased due to a greater exposure to unsafe sexual behaviors, such as unprotected sexual intercourse and high numbers of clients/sexual partners (15).The prevalence and associated risk factors for M. genitalium have been investigated both in the general population and among populations at high risk for STIs in sub-Saharan Africa, Asia, the United Kingdom, and the United States (4, 16-23). Across many of these studies, a young age, little education, single marital status, and high numbers of sex partners remained consistently associated with infection (4,9,16,18,21,23,24). Findings are less consistent among the few studies that examined risk factors among FSWs. In the literature, studies have shown similar associations of M. genitalium infection with basic demographic factors, such as education and marital status. However, there is less agreement for sexual-behavioral and clinical correlates, such as condom use, duration of sex work, and history of STIs (16,18,23). Chinese sex workers who did not present STI symptoms in the year prior to the study were more likely to have infection with M. genitalium than those who did (23). In contrast, a study conducted in sub-Saharan Africa found that sex workers who presented clinical symptoms were more likely to have M. genitalium infection than those who were asymptomatic (18).In studies examining concurrent M. genitalium infection with other STIs in the general population, M. genitalium was found to be associated with urethritis, cervicitis, and PID (25-28). However, more-recent research indicates the role of M. genitalium ...