Introduction: Preoperative elective intra-aortic balloon pump (IABP)prompts improve result in helpless left ventricular function patients going through coronary artery bypass graft (CABG).The aim of this work was to assess the efficacy of preoperative intra-aortic balloon pump treatment on postoperative cardiac performance, morbidity and mortality. Method: a prospective, cohort study was conducted on 40 patients with preoperative left ventricular ejection fraction< 40%, who went through coronary artery bypass graft. These patients were divided preoperatively into two groups: Group I (N. =20) received intraaortic balloon pump insertion 1-2 hours prior to aortic cross clamp. Group II (N. = 20) control group who did not receive intra-aortic balloon pump preoperatively. Results: Both group were matched regarding age, sex distribution and body surface area, mean cardiac index in group I was significantly higher(2.5± 0.21 vs. 2±0.32) (P