ABSTRACT Background/Objective: To examine N-acetylcysteine’s renoprotective effect in adult cardiac surgery Methods: PubMed, Ovid Medline, and Embase were searched for randomised controlled trials published between January 1990 and November 2019 that investigated the effect of N-acetylcysteine in preventing acute kidney injury in patients undergoing cardiac surgery. Cochrane Library was searched to identify any prior systematic review or meta-analysis. Eligibility Criteria: Randomised controlled trials that assessed the effect of N-acetylcysteine in comparison to placebo by measuring the incidence of acute kidney injury. Two independent reviewers extracted the data and assessed the risk of publication bias of included studies. Results: Overall meta analytic estimates of all 10 included trials was controversial, showing that N-acetylcysteine did not have a significant effect (odds ratio: 0.84, 95% confidence interval 0.64 to 1.10). However further meta analytic estimates comparing the dosage and timing of NAC administered suggested that the administration of high dosages of NAC perioperatively would have significant benefit in preventing acute kidney injury. Conclusion: This study suggests that N-acetylcysteine must be administered at high dosages perioperatively to have a significant effect in reducing the incidence of acute kidney injury. However, only one out of the 10 included trials administered NAC high dosages perioperatively. Although it is worth noting that it is the only included trial to show a significant benefit in reducing the incidence of acute kidney injury (odds ratio: 0.30, 95% confidence interval 0.11 to 0.81), further studies should be conducted to confirm the renoprotective effect of administering high dosages of NAC perioperatively.