The concept of intraaortic balloon counterpulsation (IABC) was developed in the late 1960s, primarily for use in cardiogenic shock. Since that time, many published reports have documented the efficacy of this mechanical assist device in an expanding number of clinical situations. Research has shown that intraaortic balloon counterpulsation increases coronary flow velocity and decreases afterload, thus favorably affecting myocardial oxygen supply and demand. This article offers a review of the concepts and mechanics of IABC, as well as current indications and contraindications for use. The nurse must be able to recognize and address potential complications to ensure positive patient outcomes.