Risk factors for superior vena cava perforations following central venous catheterization for total parenteral nutrition were identified in a retrospective study of 1058 catheters in 853 patients; 540 of these catheters were size 16-gauge (51%) and 518 size 14-gauge (49%). Of the size 14-gauge catheters, 274 (53%) were right-sided and 244 (47%) were left-sided subclavian catheters. Four patients (0.4%) had superior vena cava perforation. All had left-sided large bore 14-gauge catheters. All patients experienced acute symptoms and all had pleural effusions. There was no mortality directly related to vascular erosions. Two risk factors were identified for this complication: (1) catheters originating from the left side (p less than 0.05), or (2) large catheters (size 14-gauge or larger) (p less than 0.01). We conclude that large bore or left-sided central venous catheter placement represents an increased risk of superior vena cava perforation.