The Nutrition Support Team developed a standardized parenteral nutrition (PN) order form for the newly introduced total nutritional admixture (TNA) system. The new order form (TNA-Form) is oriented toward the physician, providing prescription guidelines and standing orders for the initiation and discontinuation of PN. The form replaced an older one (TPN-Form) originally designed for pharmacy use. Over two 4-month periods, the usefulness of the new TNA-Form was compared with that of the old TPN-Form, with reviews of the completeness and safety of all PN prescriptions. When prescription errors, errors of dosage, or errors of omission occurred, the pharmacist queried the physician. The number and the nature of the prescription errors per PN order were recorded daily for each patient. With the old TPN-Form, there were 634 prescription errors in 682 patients (93% total error rate). This rate decreased to 116 prescription errors in 1017 patients (11% total error rate) with the new TNA-Form. There were fewer errors in all categories concerning glucose and lipid concentrations, trace elements and vitamins, the use of heparin, infusion rate, and electrolyte concentrations. It was concluded that the new TNA-Form led to a substantial decrease in overall PN prescription errors, particularly errors of omission, resulting in safer, more efficacious, and more uniform provision of PN. The new TNA-Form provided the secondary benefit of an educational tool for housestaff. Because of its broad-based benefits, it was subsequently adopted by two other hospitals in the community.