Background/Aims: Acute kidney injury (AKI) is a postoperative complication after cardiac surgery with a high impact on mortality and morbidity. Nephrocheck® TIMP-2*IGFBP7 determines markers of tubular stress, which occurs prior to tubular damage. It is unknown at which time-point TIMP-2*IGFBP7 measurement should be performed to ideally predict AKI. We investigated the association of TIMP-2*IGFBP7 at various time-points with the incidence of AKI in patients undergoing elective cardiac surgery including cardio-pulmonary bypass. Methods: In a prospective cohort study, serial blood and urine samples were collected from 150 patients: pre-operative, at ICU-admission, 24h and 48h post-surgery. AKI was defined as Serum-Creatinine rise >0.3 mg/dl within 48hrs. Urinary TIMP-2*IGFBP7 was measured at pre-operative, ICU-admission and 24h post-surgery; medical staff was kept blinded to these results. Results: A total of 35 patients (23.5%) experienced AKI, with a higher incidence in those with high TIMP-2*IGFBP7 values at ICU admission (57.1% vs. 10.1%, p<0.001). In logistic regression TIMP-2*IGFBP7 at ICU admission was independently associated with the occurrence of AKI (Odds Ratio 11.83; p<0.001, C-statistic= 0.74) after adjustment for EuroSCORE II and CBP-time. Conclusions: Early detection of elevated TIMP-2*IGFBP7 at ICU admission was strongly predictive for postoperative AKI and appeared to be more precise as compared to subsequent measurements.