Introduction: Coronary artery disease (CAD) remains a significant cause of morbidity and mortality worldwide, often leading to heart failure (HF). The incidence of systolic myocardial dysfunction among CAD patients is increasing, partly due to improved survival after acute myocardial infarction (MI). Re-vascularization, particularly coronary artery bypass grafting (CABG), is recommended over percutaneous coronary intervention (PCI) in patients with reduced left ventricular ejection fraction (LVEF) and multi-vessel CAD, according to European guidelines. Objective: To ascertain the mean post-operative left ventricular ejection fraction in patients undergoing coronary artery bypass grafting at a tertiary care hospital in Karachi. To compare the mean post-operative left ventricular ejection fraction in patients undergoing single versus multiple arterial coronary artery bypass grafts. Study Design: Descriptive Cross-Sectional Study Setting: Department of Cardiac Surgery, National Institute of Cardiovascular Diseases (NICVD), Karachi, Pakistan. Duration: From January 24, 2022, to October 23, 2022. Participants: Patients meeting inclusion criteria and attending NICVD, Karachi, were enrolled after obtaining informed consent. Data Collection: Left ventricular ejection fraction (LVEF) assessments were conducted one week post-procedure and at six months. Data were electronically recorded for analysis. Results: The study included 105 patients with a mean age of 55.06 ± 10.02 years, comprising 71 (67.6%) males and 34 (32.4%) females. Post-operative LVEF at 1st week, 3rd month, and 6th month averaged 36.4 ± 3.1, 44.6 ± 6.1, and 52.5 ± 6.0, respectively. Comparison revealed a significant difference in mean post-operative LVEF at 6 months between patients receiving single arterial (49.6 ± 5.9) versus multiple arterial grafts (52.8 ± 6.1) (P = 0.007). Conclusion: This study underscores a substantial difference in mean post-operative LVEF between patients undergoing single versus multiple arterial coronary artery bypass grafts. Further well-controlled prospective trials are warranted to corroborate these findings.