Background: Coronary heart disease is the most common cause of death worldwide. It is responsible for almost a third of deaths in patients over the age of 35. Various biomarkers are currently being studied in detail for their value in predicting postoperative mortality in patients undergoing CABG. Aim: The aim of this study is to analyze the predictive value of certain blood morphological parameters in CABG and off-pump coronary artery bypass grafting (OPCAB). Methods: A total of 520 patients who underwent surgery in two consecutive years and underwent CABG (404) or OPCAB (116) were included in this retrospective study. Gender, age, comorbidities, five-year survival rate, detailed information on hospitalization, surgery, intensive care unit parameters and preoperative blood samples from the cubital vein were recorded. Inverse propensity treatment weighting was applied to adjust for confounding factors at baseline. Results: No differences were found between OPCAB and CABG as an isolated comparison. In the standardized population, patients with abnormal lymphocyte counts had an increased risk of death at one-year and five-year follow-up. In the standardized population, abnormal red blood cell distribution width (RDW-SD), neutrocyte-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) were associated with increased mortality in each period analyzed. Conclusions: Abnormal PLR, RDW-SD and NLR are associated with increased early and late mortality in patients undergoing CABG and OPCAB. Abnormal lymphocytes are only associated with increased late mortality.