Objective: The objective of this study is to investigate the hematological changes that occur during and after cardiopulmonary bypass in patients undergoing heart surgery. The study aims to analyze various hematological parameters, such as Hemoglobin (Hb), Activated Clotting Time (ACT), Prothrombin Time (PT), Activated Partial Thromboplastin Time (aPTT), International Normalized Ratio (INR), RBC count, WBC count, Platelet Count, Adenosine Diphosphate (ADP) induced aggregation, Arachidonic Acid (AA) induced aggregation, Fibrinogen Concentration, Albumin, Total Protein, and Urine Output.