Controversy concerning the pulmonary artery catheter (PAC) and its use as a bedside clinical tool continues to be a significant bone of contention. In the pursuit of evidence-based medicine, a substantial effort has been made over the last 25 years to demonstrate the benefit or lack thereof of PAC-led therapy, and this endeavor still persists with large, randomized, clinical trials currently in progress both in the United States and in the United Kingdom. This article reviews the core evidence for and against PAC efficacy and safety and considers the most appropriate method for validation of such a device.