Intra-aortic balloon pump (IABP), the most widely used mechanical circulatory support device, involves placing a balloon catheter in the descending aorta, which inflates and deflates using the counterpulsation method. By increasing myocardial perfusion during diastole and reducing afterload during systole, IABP enhances myocardial function by optimizing myocardial oxygen supply and demand. It serves as a temporary myocardial measure for cardiac recovery or as a bridge to definitive therapy for failing hearts. This chapter provides a concise overview of IABP components, counterpulsation principles, applications, and management, including troubleshooting of common IABP problems.