<jats:sec> <jats:title>Aim</jats:title> <jats:p>To assess the impact of the different stages of acute kidney injury (AKI) on the prognosis of patients hospitalized with decompensated cirrhosis.</jats:p> </jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>This was a prospective cohort study of consecutive patients admitted in two tertiary hospitals in southern Brazil. Participants were considered eligible if they were admitted for acute decompensation of cirrhosis. The main exposure factor was the onset of AKI. AKI stages were defined according the European recommendations. The outcomes evaluated were survival time and death rates at 28 and 90 days from hospital admission. A χ<jats:sup>2</jats:sup> test was used to compare mortality between groups. Kaplan–Meier survival analyses were undertaken assessing time to event as days from AKI diagnosis to death or liver transplant.</jats:p> </jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>Two hundred and five patients were included in the study, and 121 met the criteria for AKI. Patients with AKI 1b, AKI 2 and AKI 3 had higher 90-day mortality than patients without AKI (<jats:italic toggle="yes">P</jats:italic> = 0.008, <jats:italic toggle="yes">P</jats:italic> < 0.001 and <jats:italic toggle="yes">P</jats:italic> < 0.001, respectively). However, there was no difference in 90-day mortality when patients with AKI 1a were compared with those without AKI (<jats:italic toggle="yes">P</jats:italic> = 0.742). The mean survival of patients without AKI was higher than that of patients with AKI 1b (591.4 and 305.4 days, respectively, <jats:italic toggle="yes">P</jats:italic> = 0.015), while there was no significant difference between the mean survival of patients without AKI and that of patients with AKI 1a (591.4 and 373.6 days, respectively, <jats:italic toggle="yes">P</jats:italic> = 0.198).</jats:p> </jats:sec> <jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Only AKI ≥1b seems to substantially impact mortality of patients hospitalized for acute decompensation of cirrhosis.</jats:p> </jats:sec>