Background: Nutrition delivery, is a key component in the management of critical illness. Traditional scoring systems are inadequate in the intensive care unit (ICU), as patients are sedated. Our study examines the associations between calorie and protein adequacy, 28-day mortality, and modified Nutrition Risk in Critically Ill (mNUTRIC) score and identify at-risk ICU patients who may benefit more from nutrition intervention.Methods: Prospective observational study of adults admitted for >24h to the ICU of a tertiary care hospital during a period of 7 months. Data were collected on nutrition delivery, mNUTRIC score, use of mechanical ventilation, and ICU/hospital length of stay (LOS). Multivariate logistic regression analysis was done with 28-day mortality as the primary outcome. Results: Two hundred forty-eight patients were recruited for the study with 60% male, 40% female, mean age 60.8 ± 14.7, and body mass index of 24.2 ± 4.8.Patients with inadequate calorie and protein delivery had significantly higher 28-day mortality than those with adequate provision (P=.032 and P =. 017). In bivariate logistic regression analysis, mNUTRIC score (odds ratio [OR], 1.802; 95% CI, 1.042-3.117; P = .035) and adequacy of energy (OR, 1.92) and protein (OR, 2.49) correlate with 28-day mortality. The Kaplan-Meier survival curve showed a survival benefit in the ≥80% energy and protein group among the total patients and was also significantly associated with lower hospital and ICU LOS, even after matching (log-rank test, P < 0.001).