BACKGROUND Orthotopic heart transplantation (HTX) remains the ultimate treatment option in patients with end-stage heart failure, endorsed by the European Society of Cardiology guidelines. The aim of the study is a complex evaluation of the postoperative bleeding after HTX and its influence on short-term outcome. MATERIAL AND METHODS A retrospective cohort study consisted of 53 patients (4 females and 49 males, median age 52.5 years, IQR 17 years) who underwent HTX in the Department of Cardiovascular Surgery and Transplantology of John Paul II Hospital in Krakow between 2007 and 2014. RESULTS The median chest tube output within first 24 hours after the surgery was 695 (550-870) mL. Bleeding decreased throughout the observation (p=0.000). The first postoperative hemoglobin level was a significant predictor of excessive blood loss (p=0.017). The volume of chest tube output increased the duration of mechanical ventilation (p=0.046) and the incidence of re-exploration after first 24 hours of observation (p=0.049). In patients with higher chest tube output, more packed red blood cells (PRBC), fresh frozen plasma (FFP), and platelet (PLT) transfusions were required (p=0.000, p=0.019, and p=0.000, respectively). Early rethoracotomy (within the first 24 hours post-surgery) increased the in-hospital mortality (p=0.021; OR 7.43 [1.36-40.64]). CONCLUSIONS The study demonstrates the importance of postoperative bleeding and bleeding complications for short-term outcome in our post-HTX cohort. Throughout the analysis, the first postoperative hemoglobin level was detected to be a significant predictor of postoperative blood loss.