BACKGROUND Information about HBV sero-markers, infection stages and genotypes in HIV-1 infected and uninfected injection and non-injection drug users (IDUs) in Kenya remains elusive. METHODS A cross-sectional study examining HBV sero-marker, infection stages and genotypes was conducted among HIV-1 infected and uninfected, respectively, IDUs (n = 157 and n = 214) and non-IDUs (n = 139 and n = 48), and HIV-1 uninfected non-drug using controls (n = 194) from coastal, Kenya. HBV sero-marker and infection stages were based on HBV 5-panel rapid test plasma sero-reactivity. DNA was extracted from acute and chronic plasma samples and genotypes established by nested-PCR and direct sequencing. RESULTS HBsAg positivity was higher in HIV-1 infected IDUs (9.6%) relative to HIV-1 uninfected IDUs (2.3%), HIV-1 infected non-IDUs (3.6%), HIV-1 uninfected non-IDUs (0.0%) and non-drug users (2.6%; P = 0.002). Contrastingly, HBsAb positivity was higher in HIV-1 uninfected IDUs (14.6%) and non-IDUs (16.8) in comparison to HIV-1 infected IDUs (8.3%), and non-IDUs (8.6%), and non-drug users (8.2%; P = 0.023). HBcAb positivity was higher in HIV-1 infected IDUs (10.2%) compared to HIV-1 uninfected IDUs (3.3%), HIV-1 infected non-IDUs (6.5%), HIV-1 uninfected non-IDUs (2.1%) and non-drug users (4.6%; P = 0.038). Acute (5.7%, 1.4%, 0.0%, 0.0% and 1.5%) and chronic (5.1%, 0.9%, 3.6%, 0.0% and 1.5%) stages were higher in HIV-1 infected IDUs, compared to HIV-1 uninfected IDUs, HIV-1 infected and uninfected non-IDUs and non-drug users, respectively. However, vaccine type response stage was higher in HIV-1 uninfected IDUs (15.4%) relative to HIV-1 infected IDUs (6.4%), and HIV-1 infected (6.5%), and uninfected (10.4%) non-IDUs, and non-drug users (5.7%; P = 0.003). Higher resolved infection rates were also recorded in HIV-1 uninfected IDUs (11.2%) compared to HIV-1 infected IDUs (8.3%), and HIV-1 infected (7.2%), uninfected (6.3%) non-IDUs, and non-drug users (6.7%; P = 0.479), respectively. Only A1 genotype showing minimal diversity was detected among the study participants. CONCLUSION HBV sero-markers and infection staging are valuable in diagnosis and genotyping of HBV infections. Among IDUs, higher HBsAg and HBcAb positivity in HIV-1 infected and higher HBsAb positivity in HIV-1 negative IDUs suggests frequent exposure. Additionally, HBV genotype A is the dominant circulating genotype in both high and low risk populations of Kenya.