An infection rate was calculated for all subclavian catheters inserted during a 12-month period. The overall, single lumen, and triple lumen infection rates were 1.7% (42/2,431), 0.4% (8/1,936), and 6.9% (34/495), respectively. After excluding single lumen catheters in patients in a surgical cardiovascular unit who appeared to have a decreased risk of infection, the overall, single lumen, and triple lumen rates were 3.7% (42/1,140), 1.2% (8/645), and 6.9% (34/495), respectively. Within this group, 11.8% (281237) of the catheters used for total parenteral nutrition (TPN) were infected, whereas 1.6% (14/903) of the non-TPN catheters were infected. Of patients receiving total parental nutrition through a triple lumen catheter, 14.5% (25/172) became infected, whereas 4.6% (3/65) of the patients receiving total parental nutrition through a single lumen catheter became infected. Single and triple lumen patient groups appeared comparable based on average age, death rate, immunosuppression, underlying disease, and duration of catheterization, but the risk of infection was approximately three times greater for patients receiving total parental nutrition through a triple lumen catheter.