Abstract: AIM To study the risk factors of renal recovery in post-cardiac surgery patients with acute kidney injury (AKI) and under renal replacement therapy (RRT). METHODS We retrospectively screened cardiac surgery patients with AKI and under RRT between November 2010 and March 2015. Demography characteristics, clinical scores, laboratory data and therapeutic outcomes were collected. Renal recovery was defined as alive and free of RRT for 14 consecutive days. RESULTS The present study included 185 patients with average age (50.2±13.1) years. Of the included patients, 67.6% were male and the pre-operation average eGFR was 78.5 (44.7-82.0) ml/(min·1.73 m²). During the follow-up, 95 patients (51.4%) had renal recovery. The multivariate logistic regression analysis showed that pre-operation eGFR (HR=0.52, 95%CI 0.46-0.77; P=0.043), the amount of red cell infusion during the surgery (HR=1.05, 95%CI 1.01-1.26; P=0.046) and the use of vasoactive agent during RRT (HR=1.26, 95% CI 1.09-1.56; P=0.037) were the independent risk factors for failure of renal recovery. CONCLUSION Lower pre-operation eGFR, more red cell infusion during the operation and the use of vasoactive agents during RRT may suggest lower possibility of renal recovery for post-cardiac surgery patients with AKI and under RRT.