BACKGROUND AND AIMS: Current creatine-based criteria for defining acute kidney injury (AKI) are validated in general hospitalised patients but their application to cirrhotics (who are younger and have reduced muscle mass) is less certain. We aimed to evaluate current definitions of AKI (acute kidney injury network (AKIN) criteria) in a population of cirrhotic patients and correlate this with outcomes. METHODS: We prospectively identified patients with AKI and clinical, radiological or histological evidence of cirrhosis. We compared them with a control group with evidence of cirrhosis and no AKI. RESULTS: 162 cirrhotic patients were studied with a mean age of 56.8±14 years. They were predominantly male (65.4%) with alcoholic liver disease (78.4%). 110 patients had AKI: 44 stage 1, 32 stage 2 and 34 stage 3. They were well matched in age, sex and liver disease severity with 52 cirrhotics without AKI. AKI was associated with increased mortality (31.8% vs 3.8%, p<0.001). Mortality increased with each AKI stage; 3.8% in cirrhotics without AKI, 13.5% stage 1, 37.8% stage 2 and 43.2% stage 3 (p<0.001 for trend). Worsening liver disease (Child-Pugh class) correlated with increased mortality: 3.1% class A, 23.6% class B and 32.8% class C (p=0.006 for trend). AKI was associated with increased length of stay: median 6.0 days (IQR 4.0-8.75) versus 16.0 days (IQR 6.0-27.5), p<0.001. Multivariate analysis identified AKI and Child-Pugh classes B and C as independent factors associated with mortality. CONCLUSIONS: The utility of AKIN criteria is maintained in cirrhotic patients. Decompensated liver disease and AKI appear to be independent variables predicting death in cirrhotics.