Objective: Factors such as increased metabolic needs and inadequate calorie and protein intake increase the risk of malnutrition in critically ill children admitted to the pediatric inten- sive care unit. This study aimed to determine the risk of malnutrition and associated clinical outcomes. Materials and Methods: Data from all patients aged 1 month to 18 years in 4 pediatric inten- sive care units in Adana, Turkey, were prospectively collected. Patient anthropometric data, the duration of mechanical ventilation, the length of stay in pediatric intensive care unit, 60-day mortality, nutritional status, and calorie and protein intake were recorded. Results: A total of 111 patients were included in the study. There was a significant difference between survivor and non-survivor patients in terms of calorie and protein intake 48 hours after admission and protein intake on the seventh day after admission (P = .001, P = .000, and P = .003, respectively). No significant correlation was found between the length of pediatric intensive care unit stay, sepsis, and calorie intake in the first week. It was found that 1 g/kg/ day increase in protein intake on the seventh day of intensive care hospitalization decreased the risk of mechanical ventilation by 0.49 times (P = .035; sensitivity: 83.3%; specificity: 34.5%). Conclusion: Nutritional status should be evaluated fully in patients admitted to the pediatric intensive care unit and early detected malnutrition should be monitored closely to determine the need for early intervention. The risk of developing malnutrition is high in critically ill children. Providing the necessary energy and protein intake with nutritional therapy affects the clinical course in children with critical illness. Protein intake causes prolongation of mechanical ventila- tion time, delaying clinical recovery.