From July 1977 to December 1982, 6,245 patients requiring cardiac and noncardiac operations had pulmonary artery (PA) catheterizations for perioperative monitoring. Their ages ranged from 4 to 94 years. PA catheters were inserted through the external or internal jugular vein in 6,146 patients, while arm veins were used in 99 patients. Complications included persistent PVCs requiring therapy in 193 (3.1%), right bundle branch blocks in three (0.048%), left bundle branch and complete heart block each in one patient (0.016%), intrapulmonary hemorrhage in four (0.064%), minor pulmonary infarcts in four (0.064%), perforation of right ventricle in one (0.016%), and death from uncontrollable pulmonary hemorrhage in one patient (0.016%). This investigation reveals a low incidence of morbidity associated with PA catheterization.