Background: Tissue inhibitor of metalloproteinase-2 (TIMP-2) is a member of the matrix metalloproteinase family, inducer of G1 cell cycle arrest, it is a marker of cellular stress in the early phase of tubular cell injury caused by a wide variety of insults Aim and objectives: The aim of this work was to study if urinary TIMP-2 can be used as one of early biomarkers of acute kidney injury after cardiac surgery. Subjects and Methods: This was cross sectional study was conducted in collaboration between the Internal Medicine, Cardiothorathic and Clinical pathology departments, Faculty of Medicine, Zagazig University Hospitals. A total number of 50 patients were included and classified into two main groups: Group I: included 25 patients who undergone coronary artery bypass graft. Group II: included 25 patients who undergone valve replacement surgery. The patients were reclassified after the procedure into two groups: AKI group: defined on 24 h creatinine level elevation either by 25% of the basal level or by 0.3 mg/dl above the basal level. No AKI group: No rise of the serum creatinine level after 24 hours of the operation. The duration of the study ranged from12- 18 months. Results: There was highly significant difference regard urinary TIMP-2 and serum Cystatin C after 24 hours post operative in AKI group than non AKI group. Also we found that all markers significantly increased postoperatively than preoperative in AKI group only. But Cr, and BUN postoperative were significantly higher at AKI group later after 48 H and 72 H, and GFR significantly decreased than No AKI group. Conclusion: On the basis of recent evidence, urinary TIMP-2 is an effective predictive factor of AKI.