Background: Conflicting reports on the efficacy of intra-aortic balloon pump (IABP) during percutaneous coronary intervention (PCI) incited us to evaluate the utility of IABP in patients with acute myocardial infarction (AMI). Methods: Randomized clinical trials comparing patients, who received IABP vs. control (no IABP) during PCI, were hand-searched from MEDLINE, Cochrane, and EMBASE databases using the terms "intra-aortic balloon pump, percutaneous coronary intervention, myocardial infarction, acute coronary syndrome". Mortality rate (30-day and 6-month mortality) was the primary outcome, while the secondary outcomes included 30-day bleeding rate, reinfarction rate, revascularization rate and stroke rate. Results: Pooled results of the seven trials identified indicated that the 30-day and 6-month mortality rate were not significantly different between the IABP and control groups. However, in patients with MI, but without cardiogenic shock (CS), IABP was associated with lower odds of 30-day mortality (OR = 0.35, p = 0.015) and 6-month mortality (OR = 0.41, p = 0.020). The pooled results of 30-day bleeding rate was not significantly higher in patients with IABP than the control group, but for the patients with high risk PCI without CS, it was higher in patients with IABP than the control group (OR = 1.58, p = 0.009). The re-infarction, revascularization, and the stroke rate at 30 days of follow-up were not significantly different between the two groups. Conclusions: The present results do not favor the clinical utility of IABP in patients suffering high-risk PCI without CS and AMI complicated with CS. However, in patients with AMI, but without CS, IABP may reduce the 30-day and 6-month mortality rate.