Background: Female sex workers (FSW) are a vulnerable and a high risk group in the acquisition of sexually transmitted infections and cervical intraepithelial lesions (CIL). This may be attributed to their exposure to high risk factors such as smoking, sex at early age, high parity, long use of oral contraceptives, and unprotected sex among others. They are frequently infected by Human Papilloma Virus (HPV) which predisposes them to CIL. Although these factors increase the odds of developing CIL, many women with these risk factors do not acquire CIL. Objectives: To evaluate the risk factors associated with CIL among FSW and to compare them with those of a control population (CP) attending a Gender Violence Recovery Center at The Nairobi Women’s Hospital in Nairobi, Kenya. Design: A comparative descriptive study. Method: FSW attending entertainment establishments were recruited using snow balling technique while the CP were women attending clinics at the hospital during the study period. The purpose of the study was explained to both study groups. Those with written consents were interviewed using a structured questionnaire and screened for CIL. Results: A total of 352 participants were recruited for both arms with an average age of 36.23 (SD=9.6) years and an age range of 21 to 60 years. On overall, 203 (58%) females had their sex debut at or above 21 years while 149 (42%) had their first sexual intercourse earlier than 21 years of age. Most participants 204 (58%) had 2 or less children while 148 (42%) had more than 2 children. In this study 87 (25%) used oral contraceptives, 67 (19%) used condoms while 109 (31%) used dual contraception. FSW smokers were 85 (53%) with the majority, of the smokers (97%) being below 50 years of age. In the CP smokers were 102 (58%) with the majority (97%) being below 50 years of age. The prevalence of CIL in FSW was 24% compared to 24% in the control group. Conclusion: This study shows no correlation between lifestyle behaviors as risk factors on the prevalence of CIL because the prevalence in FSW and CP was at per (24%). Therefore there may be more underlying reasons towards the prevalence of CIL other than the lifestyle behaviors.