Introduction: Malnutrition, as defined by the World Health Organization (WHO), occurs when the body does not receive sufficient nutrients or energy to meet growth, maintenance, and functional needs. Severe malnutrition in children increases the risk of death, disease episodes, complications, and prolonged illnesses. Therefore, early nutritional support is crucial in pediatric critical care settings. In cases where oral feeding is not feasible, enteral feeding (EN) becomes necessary to provide adequate energy. However, despite its advantages, feeding intolerance remains a significant challenge. This study aims to determine the prevalence of feeding intolerance among critically ill children in the Pediatric Intensive Care Unit (PICU). Method: This cross-sectional study was conducted at the Akbar Pediatric Subspecialty Center's PICU in Mashhad, Iran between March and April 2022. The evaluation focused on nutritional adequacy and feeding intolerance. Results: A total of 72 patients were included in this study with a majority being girls. Approximately 30 percent of patients exhibited severe malnutrition based on their BMI Z-score (<-3). Boys were more affected than girls in this regard. Most patients received a combination of EN and parenteral nutrition (PN) to fulfill their energy and protein requirements successfully. In most cases, children consumed over 66% of their energy needs through these methods. Feeding intolerance primarily manifested as vomiting and regurgitation (47%), followed by high gastric residual volume (GRV) (36.1%) and abdominal distention (34.7%). Conclusion: The findings from our study highlight the prevalence of malnutrition within PICU settings along with common complications associated with feeding intolerance such as vomiting and regurgitation. Standardizing a definition for feeding intolerance could prove beneficial for improving research protocols aimed at effectively managing this condition.