Background Condomless sex and particularly anal intercourse (AI) with partners and clients are among the primary drivers of the HIV epidemic among female sex workers (FSW) in Iran. However, little is known about AI prevalence and its correlates among FSW in Iran.

Methods Data were obtained from a bio-behavioral surveillance survey of 1347 FSW conducted across 13 major cities in Iran in 2015. FSW were eligible if they (i) were ≥18 years of age, (ii) reported penetrative sex with more than one client in the previous year. Date were collected through one-on-one interviews using a standardized risk assessment questionnaire. A modified Poisson regression model was used to examine the correlates of recent (i.e., past-month) HAS and adjusted prevalence ratio (APR) and 95% confidence intervals (CI) were reported (analytic sample: 1337).

Results Recent AI was reported by 18.5% (95% CI: 13.0, 25.6) of the participants; of whom, 196 (80%) reported inconsistent condom use during their AIs in the previous month. Recent AI was positively associated with younger (≤18) age (APR: 1.24; 95% CI: 1.06–1.59), history of group sex in the previous month (APR: 1.62; 95% CI: 1.08–2.44), higher number of clients in the previous month (APR: 2.35; 95% CI: 1.38–4.00), and weekly use of alcohol (APR: 1.62; 95% CI: 1.12–2.34). Conversely, recent AI was negatively associated with being married (APR: 0.52; 95% CI: 0.34–0.80) and having had protected sex with their last client (APR: 0.73; 95% CI: 0.54–0.97).

Conclusion About one in five FSW reported engaging in recent AI; most of which were condomless. AI was more frequent among younger FSW and those with higher number of clients and problematic Alcohol use. Harm reduction and condom promotion efforts in Iran should include effective packages to address high prevalence of unsafe AI and re-emphasize the importance of condom use for both FSW and their partners/clients.

Disclosure No significant relationships.