We analyzed in-hospital mortality for patients treated with intra-aortic balloon counterpulsation from the Benchmark Counterpulsation Outcomes Registry (n = 25,136). In-hospital mortality was higher in patients who received only medical interventions (32.5%) than in those who underwent percutaneous (18.8%) and surgical (19.2%) interventions, and was greatest in the first days after hospital admission for all 3 intervention types. Therefore, diagnostic evaluation and treatment decisions should be made as early as possible, and physicians should be aware of associated risk factors in making choices for patients.