This research examined differences in parenteral nutrition (PN) macronutrient (non-protein calories (NPC), grams of protein (PRO), carbohydrate to fat ratios) calculations between medical residents (MRs) and registered dietitians (RDs). This was conducted through a chart review of orders and notes from a midwest teaching hospital. The results showed that MRs prescribed on average 300 NPC more than RDs (n=102, SD ± 651.136, t = 4.45, df = 93, p = < 0.001). Additionally, despite recommendations from the American Society of Parenteral and Enteral Nutrition, MRs prescribe more macronutrients for obese patients and less macronutrients for normal and underweight patients when compared to RDs (PRO: F (3, 95) = 3.39, p = 0.021; NPC: F (3, 95) = 6.22, p = 0.001). This research stands to add to the body of knowledge in support of RDs obtaining greater PN privileges in the clinical setting.