Background and Objectives: The optimal delivery of enteral nutrition (EN) may improve clinical outcomes in critically ill patients; thus, optimal EN protocols should be developed. The purpose of this study was to evaluate the impact of implementing an EN protocol on the improvement of EN practices and on the clinical outcomes of critically ill patients. Methods and Study Design: This was a retrospective study with prospectively collected data. Multidisciplinary working group developed an evidence-based EN protocol based on an extensive review of literature and existing guidelines. Subjects included patients consecutively admitted to the ICU who received EN for more than 24 hours. EN practices and clinical outcomes were compared before and after implementation of the protocol. Results: A total of 270 patients were included, 134 patients before implementation and 136 after implementation of the protocol. EN was initiated earlier (35.8 vs 87.1 hours, p=0.001) and more patients received EN within 24 hours (59.6% vs 41.0%, p=0.002) after implementation of the protocol. The interval between start- ing EN and reaching the caloric goal was not different, but more patients reached the caloric goal after implemen- tation (52.2% vs 38.3%, p=0.037). The post-implementation group was given more prokinetics and less parenter- al nutrition. The incidences of diarrhea and gastrointestinal bleeding significantly decreased following implemen- tation of the protocol. There was no difference in clinical outcomes including in-hospital mortality and length of hospital and ICU stay. Conclusion: The implementation of the EN protocol significantly improved the practices of EN and decreased complications in critically ill patients. Clinical outcomes were not different before and after implementation.