The optimal measuring timing of Cystatin C (CysC) for early detection of contrast-induced acute kidney injury (CIAKI) remains un-studied. We conducted this systematic review and meta-analysis study to elucidate further on this issue. We searched PubMed, MEDLINE, and Embase from inception until March 2018 for studies evaluating the diagnostic accuracy of CysC for predicting CIAKI in patients exposed to contrast agents during diagnostic examinations or cardiac/peripheral catheterizations. A total of 10 relevant studies, comprising 2554 patients, were included. The included studies were divided into two groups: