Introduction We evaluated predictors of consistent condom use among female sex workers (FSWs), a core group for controlling the spread of HIV.

Methods In an analysis of data collected in 2004–2005 from 140 Kenyan FSWs who completed questionnaires administered during a baseline study visit and three bimonthly follow-up visits, we used a case-crossover design to identify predictors of consistent condom use during all coital acts in the preceding 2 weeks, overall and by partner type.

Results Participants (n=140) completed the baseline visit and 390 bimonthly follow-up visits. Alcohol use during sex was negatively associated with consistent condom use with helping partners (defined as regular sex partners to whom the woman could go for help or support if needed) (adjusted odds ratio [AOR], 2.6, 95% confidence interval [CI] 1.0–6.5) but not associated with condom use with other partners. Coital frequency was associated with condom use with other partners only. Women who reported 1–5 (AOR 11.0, 95% CI 4.3–28.3) or 6–9 recent coital acts (AOR 3.8, 95% CI 1.7–8.8) with other partners were more likely to report consistent condom use with those partners than were women who reported ≥10 acts. Having a recent partner delay payment was inversely associated with consistent condom use with helping, other, or all partners.

Conclusion Correlates of consistent condom use differed by partner type. By using a case-crossover design, we were able to identify potentially modifiable factors associated with consistent condom use by FSWs who used condoms consistently with a given partner type during some periods but not others.