In the ever evolving field of cardiovascular medicine and coronary intervention, the intra-aortic balloon pump (IABP) is a mature technology, which still plays an important role. The balloon pump invasively supports patient hemodynamics by augmenting diastolic perfusion and increasing diastolic blood pressure, thereby increasing coronary perfusion and reducing afterload. Its efficacy has been demonstrated in a multitude of clinical situations, including acute coronary syndromes, high-risk coronary interventions, cardiogenic shock, and cardiovascular surgery. The potential complications of aortic counterpulsation are serious, although much lower than once feared. With proper patient selection, insertion technique, and management, the IABP is a powerful tool to assist in the treatment of patients with cardiovascular disease. This article will review the hemodynamics, indications, and complications associated with its use.