Background: Long-acting reversible contraception (LARC) are the most effective and reliable contraceptives for female sex workers (FSWs) and require periodic users’ involvement only at the time of application or re-application. However, information on LARC use among FSWs in Uganda is scarce. To fill this gap, we determined the prevalence of LARC use among FSWs and examined factors associated with LARC use among FSWs operating in Gulu district, Northern Uganda.Methods: Across-sectional study was conducted among 300 FSWs aged 18 years and above and operating in Gulu district. Semi-structured questionnaires were used to measure factors associated with the use of LARC: intrauterine device (IUD), Implants, and injectables. Data analyses were conducted using STATA 14.0 and restricted to 280 non-gravid adult FSWs aged 18-49 years who were not on permanent contraception method. To examine factors associated with LARC use, prevalence ratios (PR) with robust standard errors were computed using Poisson regression.Results: Among the participants, the mean age (SD, range) was 26.5 (5.9, 18 - 45) years, 53.2% never married, 66.1% reported consistent condom use independent of LARC, 58.9% had unintended pregnancy during a lifetime, 48.6% had at least one unintended pregnancy during sex work, and 37.4% had at least one induced abortion. The prevalence of LARC use was 58.6%; the majority were using Implants (48.2%), followed by injectables (42.7%), and IUDs (9.1%). Independent factors associated with LARC use included: longer duration of sex work [≥ two years] (adjusted PR=1.44, 95% CI: 1.03-2.02), higher parity [≥ two] (adjusted PR=1.13, 95% CI: 1.02-1.26), history of unintended pregnancy during sex work (adjusted PR=1.24 CI: 1.01-1.51), and being a brothel/lodge-based FSWs (adjusted PR=1.28, 95% CI: 1.01-1.63).Conclusions: There is a big gap in LARC use with only 58.6% of FSWs using LARC. LARC use was associated with longer duration of sex work, higher parity, history of sex work-related unintended pregnancy, and being a brothel/lodge-based FSW. Therefore, interventions to improve LARC use should intensively target the newly recruited FSWs, FSWs with low parity, and FSWs not based in brothels or lodges.