Central venous catheter (CVC)-related thrombus formation has been increasingly recognized as a complication in adults and somewhat less frequently in children and neonates. However, the association of CVC thrombus and pulmonary embolism (PE) has rarely been reported in infants or children, and the few existing reports primarily involve chronic, indwelling CVCs such as Broviac or Hickman catheters. During an 18-month-period of autopsy review, we found that 5 of our pediatric intensive care unit patients had autopsy-proven CVC thrombus and pulmonary embolism. All of them had prolonged mechanical ventilation for respiratory failure and required insertion of one or more short-term, temporary CVCs during the course of routine critical care management. In retrospect, signs related to CVC thrombus were present in 4 patients (3 had positive blood cultures and 1 had persistent hypertension). PE was not diagnosed until autopsy in every case. The diagnosis may have been missed because the symptoms of PE are the same as those of severe lung disease. We, therefore, advocate a heightened suspicion of CVC thrombus formation and PE in critically ill children with respiratory failure and temporary CVCs and recommend early diagnostic ultrasound to confirm the diagnosis. Once a CVC thrombus is found, subsequent pulmonary deterioration may necessitate evaluation for acute PE. Pediatr Pulmonol. 1995; 20:349–354. © 1995 Wiley-Liss, Inc.