Patients following liver transplantation are at risk to develop acute kidney injury (AKI). The aim of our study was to assess risk factors for the development of AKI and the impact of AKI on the outcome of patients after liver transplantation (OLT). In this retrospective study, we analyzed 149 patients undergoing OLT from 1/2004 to 12/2007. AKI was defined according to the KDIGO definition representing the AKIN and the RIFLE classification, and according to the need for renal replacement therapy (RRT). According to the AKIN criteria alone 14 patients, according to the RIFLE criteria alone no patient and according to both definitions 30 patients developed AKI. RRT was required in 54 patients experiencing AKI, whereas 51 patients did not develop AKI. Pre OLT serum creatinine (SCr) significantly predicted the development of AKI requiring RRT, but not AKI without RRT requirement. Survival rate was significantly inferior after 28 days, one or three years in patients with AKI requiring RRT (70.4, 46.4, 44.4% vs. 100, 92.2, 90.2%, P < 0.001). There was no difference in survival between patients experiencing AKI according to the RIFLE or AKIN criteria without RRT requirement and patients without AKI. Pre OLT renal dysfunction assessed by SCr was the most important risk factor predicting severe forms of AKI, but not milder forms of AKI. AKI requiring RRT had a detrimental impact on patients' survival, whereas milder forms of AKI were not associated with a worse outcome.