The use of parenteral nutrition (PN) is essential for patients who are unable to meet their nutrition requirements through oral or enteral nutrition. Many earlier studies have noted that PN is often inappropriately used in the hospital setting, thereby increasing the risk of associated complications and costs. A prospective study was performed at the Medical University of South Carolina (MUSC), using a nutrition support database to determine the appropriateness of PN use and the associated hospital costs for patients on 3 surgical services over a 6-month period. Appropriateness of PN therapy was determined according to the American Society of Parenteral and Enteral Nutrition (A.S.P.E.N.) guidelines. A total of 139 new PN therapies were initiated in the 6-month period. Forty percent of the cases were deemed inappropriate. A total of 573 PN days ($80,000 hospital PN costs) could have been saved if inappropriate PN therapy had not been ordered. The avoidable costs only reflect the PN solution and not the additional costs associated with laboratory monitoring, central line placement and maintenance care, nursing administration, and ongoing pharmacy and dietitian clinical management. This study illustrated that PN was not always being provided according to A.S.P.E.N. guidelines. In addition, cost savings could be achieved if PN was provided only to MUSC patients who meet these guidelines.