Entrapment of a Swan-Ganz catheter to an intracardiac structure in open heart operation is a rare but serious complication. In the intracardiac course, the catheter tends to rest against the anterior-lateral wall of the right atrium where the catheter can be caught by a suture during cannulation for cardiopulmonary bypass 1 . A Swan-Ganz catheter entrapment by a suture in the inferior vena caval (IVC) cannulation site during mitral valve replacement is presented. The diagnosis of the suture entrapment of the Swan-Ganz catheter was established by fluoroscopic observation of the specific movement pattern of the cardiac structures when manual traction was applied from outside. In conclusion, awareness of potential catheter entrapment by suture or other mechanisms should be the first step for management, when resistance is met during catheter withdrawal. Smooth partial withdrawal of the catheter prior to initiation of cardiopulmonary bypass(CPB), or at least before chest closure, to detect catheter mobility would provide an early clue for the diagnosis. (Ind J Thorac Cardiovasc Surg, 2007; 23: 283-285)