OBJECTIVES: Parenteral nutrition (PN) is used with patients when oral or enteral nutrition isn’t possible or adequate. Compared to other therapeutic interventions, relatively little is known about the real-world use of PN, the characteristics of patients who receive it, or the incidence of adverse events. Our objective was to explore PN as it is currently utilized in the United States, using a large, nationally representative inpatient database. METHODS: We examined the Premier PerspectiveTM database for all inpatients who received any PN between 2005 and 2007.  Inpatients admitted with any outcome of interest (i.e., bacterial infection, hepatic dysfunction, hypoglycemia, acute cholecystitis, and phlebitis) were excluded. Hospital (e.g., bed size, geographic location, urban/rural status), patient (e.g., age, sex, comorbidities, severity), and PN characteristics were analyzed. RESULTS: Of over 11 million inpatients in the database, 68,984 adult, 3,083 pediatric and 34,307 neonates received PN. The average age of the adult patients was 66. Whites had a disproportionally higher probability of receiving PN (73.1%) than any other ethnic group. 46.2% of PN adult patients received PN in hospitals with bed size of 250-499, followed by hospitals with bed size of 500-749 (31.5%), and hospitals with bed size 50-249 (20.3%). Among adult PN patients, 38.9% were diagnosed with a malignancy, followed by undernutrition 33.2%, renal failure 31.3%, diabetes 24.4%. peritonitis 9.0%, acute pancreatitis 8.4%, and cirrhosis 7.6%. Compared to neonates, the infection rates and bloodstream infection rates (BSI) of the adult population were much higher (infection, 49.0% vs. 10.7%; BSI 26.9% vs. 1.7%). Most patients were primarily diagnosed with intestinal or peritoneal adhesion with obstruction (ICD-9 560.81). The majority of PN adult patients used procedure of venous catheterization (ICD-9 38.93). CONCLUSIONS: Large retrospective databases provide us with extraordinary insights to understand the characteristics of this vulnerable population and the real-world use of PN.