Although acute kidney injury (AKI) often accompanies acute liver failure (ALF), its impact on long-term outcome is unknown.This study examines the incidence, severity and outcomes of AKI in patients with ALF.A total of 134 ALF patients treated at Hannover Medical School between 1995 and 2013 were retrospectively analyzed.Fifty-four ALF patients (40.3%) demonstrated AKI, as defined by the acute kidney injury network (AKIN) classification, on intensive care unit (ICU) admission, and 85 patients (63.4%) developed AKI prior to ALF recovery, emergency liver transplantation (ELT) or death. AKI severity was closely associated with other end-organ damage ( < 0.001). Follow-up creatinine levels in survivors were increased compared to baseline levels (76 versus 64 µmol/l,  = 0.003). One-hundred-and-three (76.9%) patients reached the combined endpoint of ELT or death, and 42 (31.3%) patients died within 28 days. AKIN stage 3 at ICU admission was the strongest independent predictor of 28-day overall mortality (hazard ratio 3.48, 95% confidence interval 1.75-6.93,  < 0.001) and ELT or death (hazard ratio 2.52, 95% confidence interval 1.60-3.96,  < 0.001).AKI is a frequent complication in ALF that correlates with remote organ damage and long-term creatinine levels and independently predicts outcome.