This study was undertaken to determine differences between caloric intake and requirements of critically ill, enterally fed, neurosurgical and neurotrauma patients and to determine the nature and frequency of interruptions in enteral feedings in this same population. This descriptive, prospective study was conducted in a surgical intensive care unit (ICU) in a university teaching hospital. The sample consisted of 52 mechanically ventilated, critically ill patients with a mean age of 48.96 years who were receiving enteral nutrition for at least two days. Basal energy requirements, daily nutritional intake and enteral feeding interruption characteristics were recorded for a total of 586 study days. Underfeeding due to interruptions occurred in the majority of patients for the first eight days following initiation of enteral feeding. Reasons for underfeeding were interruptions of continuous tube feedings due to medication administration via the feeding tube (31%), feeding tube displacement (27%), surgery (12%), ileus (9%), radiologic studies (9%), airway management (8%), bedside procedures (3%) and agitation (1%). The frequency of these enteral feeding interruptions may indicate inadequate nutritional support, highlighting the importance of performing daily nutritional monitoring to prevent malnutrition.