Pulmonary artery catheter (PAC) technology has changed significantly and use has decreased over the last 20 years. Barriers to use include: (a) increased patient risk with placement; (b) ability to measure similar variables via less invasive measures; (c) increased cost; (d) inaccurate measurement leading to misuse of PAC-derived variables; (e) incorrect interpretation and clinical application; and (f) lack of proven benefit for patient management. Advances in technology have allowed for continuous trending of hemodynamic parameters measured via the PAC. Patient risk is similar to that of central line placement; however risks associated with pulmonary artery infarction and rupture are inherent to the PAC. Less invasive assessment of cardiac output equals that of the PAC, whereas pulmonary capillary wedge pressure and mixed venous oxygen saturation monitoring are unique features of the PAC. Effective use of PAC data will require ongoing standardized education. More studies are needed on the cost-effectiveness of PAC monitoring as well as outcome benefits. Much of the data available from the PAC can be obtained via less invasive methods. However, the PAC continues to be useful in specific situations and remains the gold standard for comparison of new technologies. This paper discusses use of the PAC during the past 2 decades and reviews studies affecting its use in clinical practice.