Background: Drug users (DU) constitute a key population with heightened vulnerability to HIV infection due to a combination of biological, social, and structural determinants. In Cape Verde, successive bio-behavioral surveys have monitored HIV prevalence and associated risk factors among DU to guide national prevention strategies. This study synthesizes findings from the 2013, 2017, and 2023 national surveys to describe trends in seroprevalence, sexual and drug-use risk behaviors, and access to prevention and health services.Methods: A comparative analysis was conducted using three cross-sectional bio-behavioral studies employing structured questionnaires, rapid HIV testing, and qualitative interviews. Samples included 385 DU in 2013, 407 in 2017, and 501 in 2023. Data were extracted following the IMRaD framework and harmonized to evaluate temporal changes in sociodemographic profiles, drug-consumption patterns, sexual behaviors, HIV knowledge, and service uptake.Results: HIV seroprevalence remained relatively stable over the decade, with rates of 3.9% (2013), 3.1% (2017), and 2.6% (2023); however, prevalence among female DU reached 10% in 2023. Cannabis and cocaine remained the most frequently consumed illicit drugs, with early initiation (median onset 15–19 years). Sexual risk behaviors persisted, including inconsistent condom use (49.5% in 2016; 2023 values showing similar patterns), transactional sex, and limited knowledge of HIV prevention. Service access improved modestly, yet many DU continued to report stigma, discrimination, and inadequate linkage to care.Conclusions: Despite a slight decline in HIV prevalence, DU in Cape Verde remain a highly vulnerable population with persistent behavioral and structural risks. Strengthening harm-reduction strategies, scaling up HIV testing and counseling, and addressing stigma are critical to achieving national and global HIV targets