Objectives: Despite free access to antiretroviral therapy (ART) from 1996 onward, and treatment for all people living with HIV (PLWHIV) from 2013, mortality in Brazil has not homogeneously decreased. We investigated to what extent delayed ART, hepatitis coinfections and sociodemographic factors predict all-cause mortality in Brazilian PLWHIV. Design: We included PLWHIV ≥18 years, with complete CD4 count data, followed up between 2007 and 2015 in Brazil. Methods: After multiple imputation, an extended Cox model helped estimate the effects of fixed and time-varying covariates on mortality. Results: The study population (n = 411,028) were mainly male (61%), Caucasian (55%), ≤40 years (61%), heterosexually HIV-infected (71%), living in the Southeast region (48%) and had basic education (79%). HCV and HBV coinfection prevalences were 2.5% and 1.4%, respectively. During a 4-year median follow-up, 61,630 deaths occurred and the mortality rate was 3.45 [95% confidence interval (CI): 3.42-3.47] per 100 person-years. Older age, male gender, non-Caucasian ethnicity, illiteracy/basic education and living outside the Southeast and Central-West regions were independently associated with increased mortality. The main modifiable predictors of mortality were delayed ART (i.e., CD4 < 200 cells/mm at ART initiation) (adjusted population attributable fraction: 14.20% [95% CI: 13.81-14.59]), being ART-untreated (14.06% [13.54-14.59]), and ART-treated with unrecorded CD4 at ART initiation (5.74% [5.26-6.21]). HCV and HBV coinfections accounted for 2.44% [2.26-2.62] and 0.42% [0.31-0.53] of mortality, respectively. Conclusions: This study demonstrates that besides early ART and coinfection control, actions targeting males, non-Caucasians and illiterate people and those with basic education are important to reduce avoidable deaths among Brazilian PLWHIV.