Objective: to study the perception and practices of sexually transmitted infections among female sex workers in Greater Cairo. Methods: A cross sectional study including 431 of female sex workers. Results: 77.3% of participants knew about STIs. The majority (70.3%) claimed refusing sex in presence of STIs. However, unusual vaginal discharge last year was reported by 76.1% of participants, and genital ulcers by 15.5%. Only 40.1% informed their partners if having STIs and 63.1% claimed immediately starting treatment either from private or governmental facilities (45.9% and 33.6%, respectively). AIDS was known by 92.8% of participants while only 9.3% ever attended a raising awareness session. Correct methods of infection were known by 64.3% for breast milk, 78.4% from mother to her baby and 76.3% for sharing needles. Having one faithful partner, abstain from sex and proper use of condoms were the main preventive measures reported by participants (54.8%, 54.8% and 40.4%, respectively). Only 31.3% accepted taking care of an infected friend. Confidential counseling and testing for HIV was known by 57.1% but only 8.4% performed the test. Conclusion: The majorities of participants were knowledgeable about STIs and still had some misconceptions and a negative attitude towards people living with HIV. Key message: The paper addresses an issue for which limited information is available in our region due to illegal pattern of sex working. In many low prevalence countries the HIV epidemic is usually fueled by spread in most at risk population as sex workers before it turns to a generalized epidemic. The perception of HIV and STIs risk among sex workers is important to stimulate them to adopt harm reduction policies which can protect them and community from STIs including HIV infection.