BACKGROUND & AIMS: Optimal implementation of parenteral nutrition (PN) is required to promote clinical outcome and costs control. This prospective quality control study examined if PN prescription was justified and PN administration was adequate to cover the nutritional needs of patients hospitalized in the Geneva University Hospital. METHODS: Two-hundred consecutive patients receiving PN were included from Medicine, Intensive Care or Surgery Units. PN prescription was considered justified if oral feeding or enteral nutrition were contraindicated or provided less than 40% of the energy target after 5 days. PN was considered adequate if it covered 90%-110% of the recommended need for energy (i.e., 110% of the Harris-Benedict formula) and proteins (i.e., 1.2 or 1.0 g protein/kg body weight/day for patients < or = or >65 years, respectively), and was supplemented with vitamins and trace elements. RESULTS: PN prescription was justified in all but 14 patients (7%). However, PN administration was frequently inadequate: overfeeding (62%) was more often observed than underfeeding (14%), particularly among thin, elderly and female patients (P<0.01). Moreover, PN was not supplemented with vitamins and/or trace elements in 47 patients (24%). CONCLUSION: PN prescription is generally justified but PN administration is often inadequate. Further teaching of medical teams and quality control surveys are warranted to optimize PN practices.