OBJECTIVE We determined the variability in enteral feeding practices in mechanically ventilated patients in four adult intensive care units of a tertiary-care, referral hospital. METHODS Patients who had been mechanically ventilated for at least 48 h and received enteral nutrition were prospectively followed. RESULTS Fifty-five of 101 consecutive mechanically ventilated patients received enteral nutrition; in 93% of patients, feedings were infused into the stomach. Patients who were cared for in the medical intensive care unit, where a nutritional protocol was operational, received enteral nutrition earlier in their ventilatory course (P=0.004) and feedings were advanced to target rates faster (P=0.043) than those who received care in other units. The number (P=0.243) and duration (P=0.668) of interruptions in feeding did not differ by patient location. On average, patients received only 50% to 70% of their targeted caloric goals during the first 6 days of enteral nutrition. Most feeding discontinuations (41%) were secondary to procedures. Gastrointestinal intolerances, including vomiting, aspiration, abdominal distention, and increased gastric residuals, were uncommon despite allowing gastric residuals up to 300 mL. CONCLUSIONS The practice of providing enteral feeds to mechanically ventilated patients varies widely, even within one hospital. A protocol enhanced early initiation of enteral feeds and advancement to target feeding rates but did not alter the number or duration of interruptions in enteral feedings. Procedures represented the most common reason for stopping enteral feeds, and gastrointestinal intolerances (vomiting, aspiration, and increased gastric residuals) caused few feeding interruptions. The gastric route was safe and well tolerated for early enteral feeding in most mechanically ventilated patients.