BACKGROUND:In low HIV prevalence settings, understanding the transmission dynamics and the impact of drug resistance are critical to curb down the epidemic. This study aims to explore the prevalence and dynamic of transmission of HIV drug resistance mutations (DRM) among key populations in Haiti. SETTINGS:Eligible participants (naïve, treated) were selected from 7 key-populations friendly healthcare centers in Port-au-Prince Haiti, from September 2018 to July 2019. METHODS:A total of 119 HIV-1 pol sequences were analyzed from men having sex with men (MSM), female sex workers (FSW) and their sexual partners. Screening for HIV DRM was performed using the Stanford University Drug Resistance Database. Phylogenetic and network analyses using HIV-TRACE software were performed to infer putative relationships and shared DRM. RESULTS:Of the 119 participants 62.2% were male (74/119), and 75.7% of them (56/74) reported MSM as main risk factor. The overall DRM prevalence was 58.8% (70/119). DRM was observed in 37.5% of MSM (21/56), 82.2% of FSWs (37/45) and 66.7% (12/18) among FSW clients. In a multivariate model, age and FSW were significant predictors for DRM (p=0.001). Transmission network analysis found 24/119 (20.2%) genetically linked individuals forming 8 clusters. Clustering participants were mostly MSM (15/24; 62.5%). Five clusters (62.5%) had shared DRM and K103N and M184V were the main shared mutations. CONCLUSION:High prevalence of HIV DRM was observed among MSM, FSW and their clients in Port-au-Prince Haiti. Network analysis revealed frequent DRM transmission among genetically linked individuals, highlighting the need for appropriate interventions to limit HIV transmission in these high-risk populations.