During the five-year interval from January 1, 1971 to January 1, 1976 118 seriously ill adults received 2916 patient days of TPN therapy with an average infection rate of 7.6%. All patients received the benefit of a well-defined TPN catheter care protocol which emphasized regular (every 48 hours) catheter dressing changes. The lowest risk of infection, 2.7%, was seen in 73 patients who received an amino acid-glucose solution through a silicone elastomer catheter protected by an iodophor dressing. When catheter-related sepsis occurred, Staphlylococcus aureus and Candida albicans were the most common organisms cultured.