After two decades, hemodynamic invasive monitoring using a flow-directed, balloon-tipped, pulmonary artery (PA) catheter has established itself as a significant component of acute clinical care. In spite of continued recommendations for limitations, restrictions, moratoria, and even abandonment, growth in catheter use continues. Attempts to replace it by competing technologies for routine clinical practice have not been successful thus far. More than one million PA catheters are inserted in the United States annually. The clinical utility and value of the pulmonary artery catheter depend largely on the interpretation of information obtained. Clinical interpretation of data is influenced by an understanding of cardiopulmonary hemodynamics, technical skills, and professional integrity of the physician using the device. After a brief history, this article focuses on the technical aspects of the insertion procedure, choice of hardware, and acquisition and analysis of information. Indications, contraindications, and clinical utility are briefly described. Major complications from PA catheterization reported in the literature since clinical introduction of the catheter are summarized.