Studies with a comprehensive analysis of the epidemiology of acute kidney injury (AKI) in intensive care units (ICUs) are still limited in developing countries. The aim of this study is to identify the incidence and risk factors of AKI in critically ill patients from a Brazilian ICU. We performed a retrospective analysis of the records of patients admitted to a single-centre adult ICU in Brazil between 1 January 2011 and 31 December 2016. The KDIGO criteria were used to define AKI. Univariate and multivariate data analyses were carried out. We included 1,500 patients. The incidence of AKI was 40.5%, and the AKI dialysis rate was 13%. The predictors of AKI at ICU admission included hypertension [odds ratio (OR) = 1.44, p 0.017], high serum creatinine concentration [OR = 3.54; p < 0.001], low serum albumin concentration [OR = 1.42, p 0.015], high APACHE II score [OR = 2.10; p < 0.001] and high SAPS 3 [OR = 1.75; p < 0.001]. The incidence of AKI was high, and we identified the predictors of AKI among critically ill Brazilian patients. The results of this study may contribute to the implementation of targeted therapies.