Purpose Characteristics of acute kidney injury (AKI) occurring after out-of-hospital cardiac arrest (OHCA) are incompletely described. We aimed to evaluate the prevalence of AKI, identifying risk factors and assessing the impact of AKI on outcome after OHCA. Methods Single-center study between 2007 and 2012 in a cardiac arrest center in Paris, France. All consecutive OHCA patients with at least one weight measurement and one serum creatinine level available and treated by therapeutic hypothermia were included, except those with chronic kidney disease and those dead on arrival. AKI was defined as stage 3 of the Acute Kidney Injury Network (AKIN) classification. Main outcome was day-30 mortality. Factors associated with AKI occurrence and day-30 mortality were evaluated by logistic regression. Results 580 patients (71.3 % male, median age 59.3 years, initial shockable rhythm in 56.9 % of cases) were included in the analysis. AKI stage 3 occurred in 280 (48.3 %) patients. Age, male gender, resuscitation duration, post-resuscitation shock, public setting, and initial rhythm were associated with AKI stage 3. AKI stage 3 was associated with a significantly higher day-30 mortality rate OR 1.60; 95 % CI (1.05, 2.43); p  = 0.03. No independent association between AKI and neurologic outcome was observed. At day 30, 67 patients had a normal kidney function (eGFR >75 mL/min/1.73 m 2 ), and five remained dialysis-dependent. Patients with eGFR higher than 75 mL/min/1.73 m 2 at day 30 were younger and more frequently male. Conclusion AKI stage 3 was frequent after OHCA and was associated with poorer outcome. Improvement strategies in post-resuscitation care should consider AKI as a potential target of treatment.