Aims: To investigate the incidence, haemodynamic alterations and 90-day mortality of acute kidney injury (AKI) in patients with cardiogenic shock. We assessed the utility of creatinine, urine output (UO) and cystatin C (CysC) definitions of AKI in prognostication. Methods and results: Cardiogenic shock patients with serial plasma samples (n = 154) from the prospective multicenter CardShock study were included in the analysis. Acute kidney injury was defined and staged according to the KDIGO criteria by creatinine (AKI_crea) and/or UO (AKI_UO). CysC-based AKI (AKI_CysC) was defined similarly to AKI_crea. Changes in haemodynamic parameters were assessed over time from baseline until 96 h. Mean age of the study population was 66 ± 12 years and 74% were men. Median baseline creatinine was 1.12 [interquartile range (IQR) 0.87–1.54] mg/dL and CysC 1.19 (IQR 0.90–1.69) mg/L. The 90-day mortality was 38%. The incidences for AKI were: AKI_crea 31%, AKI_UO 50%, and AKI_Cysc 33%. AKI_crea [odds ratio (OR) 12.2, 95% confidence interval (CI) 4.1–36.0] and AKI_CysC (OR 2.5, 95% CI 1.1–6.1), but not AKI_UO, were independent predictors of mortality. However, a stricter UO cut-off of <0.3 mL/kg/h for 6 h was independently associated with 90-day mortality (OR 3.6, 95% CI 1.4–9.3). Development of AKI was associated with persistently elevated central venous pressure and decreased cardiac index and mean arterial pressure. Conclusions: Acute kidney injury is frequent in patients with cardiogenic shock and especially AKI_crea predicts poor outcome. The KDIGO UO criterion seems, however, rather liberal and a stricter AKI definition of UO <0.3 mL/kg/h for at least 6 h seems more useful for mortality risk prediction. Haemodynamic alterations reflecting venous congestion and hypoperfusion were associated with AKI.