OBJECTIVE Hyperglycemia may increase mortality in patients who receive total parenteral nutrition (TPN). However, this has not been well studied in noncritically ill patients (i.e., patients in the nonintensive care unit setting). The aim of this study was to determine whether mean blood glucose level during TPN infusion is associated with increased mortality in noncritically ill hospitalized patients. RESEARCH DESIGN AND METHODS This prospective multicenter study involved 19 Spanish hospitals. Noncritically ill patients who were prescribed TPN were included prospectively, and data were collected on demographic, clinical, and laboratory variables as well as on in-hospital mortality. RESULTS The study included 605 patients (mean age 63.2 ± 15.7 years). The daily mean TPN values were 1.630 ± 323 kcal, 3.2 ± 0.7 g carbohydrates/kg, 1.26 ± 0.3 g amino acids/kg, and 0.9 ± 0.2 g lipids/kg. Multiple logistic regression analysis showed that the patients who had mean blood glucose levels >180 mg/dL during the TPN infusion had a risk of mortality that was 5.6 times greater than those with mean blood glucose levels <140 mg/dL (95% CI 1.47–21.4 mg/dL) after adjusting for age, sex, nutritional state, presence of diabetes or hyperglycemia before starting TPN, diagnosis, prior comorbidity, carbohydrates infused, use of steroid therapy, SD of blood glucose level, insulin units supplied, infectious complications, albumin, C-reactive protein, and HbA1c levels. CONCLUSIONS Hyperglycemia (mean blood glucose level >180 mg/dL) in noncritically ill patients who receive TPN is associated with a higher risk of in-hospital mortality.