The coinfection of Hepatitis B virus (HBV) and human immunodeficiency virus (HIV) has been associated with increased death rates. However, the relevant research has mostly relied on serologic HBV testing [HBV surface antigen (HBsAg)]. The aim of this work was to explore the relationship of HBV viraemia with overall mortality among HIV/HBV coinfected individuals. The analysis included 1,609 HIV seropositives of a previously described cohort (1984–2003) with limited exposure to tenofovir (12%) and a median follow‐up of approximately 5 years. Those with persistent expression of HBsAg were further tested for HBV‐DNA. The data were analyzed using Poisson regression models. Totally, 101 participants were chronic carriers of HBsAg (6.28%). Of these, 81 were tested for HBV‐DNA. The median HBV‐DNA levels were 3.81 log (base‐10) International Units (IU)/ml. A third (31%) of those tested for HBV‐DNA had received tenofovir. Before developing acquired immune deficiency syndrome (AIDS), the adjusted incidence rate ratio (IRR) for all‐cause mortality of coinfected patients with HBV viraemia above the median value versus the HIV monoinfected group was 3.44 [95% confidence interval (CI): 1.05–11.27]. Multivariable regressions in the coinfected group only (n = 81) showed that one log‐10 increase in HBV‐DNA levels was associated with an elevated risk for death (IRR: 1.24, 95%CI: 1.03–1.49). HBV‐DNA levels predict overall mortality in the setting of HIV/HBV coinfection, especially during the period before developing AIDS, and could thus help prioritize needs and determine the frequency of medical monitoring. J. Med. Virol. 88:466–473, 2016. © 2015 Wiley Periodicals, Inc.