<h3>Objective</h3> The rate of excessive bleeding during open-heart surgery is 10 %. The rate of re-exploration is about 4-6 %. Therefore, it makes the mortality and morbidity increase after surgery The aim of our study is to identify the incidence of excessive bleeding and its causes during the early postoperative phases in patients undergone open-heart surgery in our institution for two years respectively. <h3>Design and Method</h3> It reviewed the hospital database to identify patients who underwent elective open-heart surgery between Jan.2019 and Jan.2021. It was defined as excessive bleeding involved measuring the amount of hemorrhage during the 1st, 2nd, 3rd, and 24th hours. We divided the cases into two groups, Group Bleeding; Group B; if excessive bleeding was present, and Group Control; Group C; if it was not. Data on demographics, clamping and pumping times in the operating room, intraoperative interventions, and clinical data such as the need for blood and blood products replacement in the ICU were recorded in the case files. Data were analyzed Student's t, Mann Witney U, Pearson Chi-Square Tests and Correlations tests. p<0.05 is statically significant. <h3>Results</h3> The incidence of bleeding was 9.7%. The rate of re-exploration was 33%. The presence of chronic lung disease was significantly higher in the bleeding group (Group B) (p=0.006). Preoperative use of anti-aggregates and diuretics was significantly higher in Group B than in Group C (p=0.00 and p=0.02, respectively). There was no significant difference between the groups in terms of bleeding and coagulation laboratory values and the use of intraoperative blood and blood products (Table 1). Postoperative use of blood and blood products was significantly higher in Group B (p<0.001, Table 2). Negative correlation between the female gender and higher EF and bleeding (p=0.032, p=0.047, respectively). A positive correlation was found between chronic lung disease, presence of CRF, diuretic, anticoagulant, EuroScore level, duration of ECD, and duration of CC and bleeding. The incidence of anemia among all patients was found at 41 % <h3>Conclusion</h3> Patients undergoing open-heart surgery under elective conditions had a 9.7% occurrence of excess bleeding and the rate of re-exploration was 33% in the early postoperative period. The presence of chronic lung disease, use of anti-aggregates and diuretics prior to surgery, a low EF score and high EuroScore, and the duration of the patient's CC and ECD were all highly predictive of excessive bleeding. In a conclusion, we thought that to improve the anemia, stopping the anti-aggregates drugs convenient time and having optimum control of the chronic diseases during preoperative evaluation might be effective for preventing excessive bleeding during the perioperative period.