Background: Early enteral feeding is considered the best nutritional support among critically ill patients, and is mostly achieved via nasogastric (NG) tube. However, nasogastric tube feeding per se may be related to a number of complications, especially increasing the possibilities of aspiration among endotracheal intubated patients. Objectives: The objective of this systematic review was to synthesize the factors associated with enteral feeding in order to prevent VAP and to describe the characteristics of these factors. Methods: A comprehensive search was undertaken involving all major databases from their inception to September 2008 using medical subject heading terms associated with enteral feeding in relation to VAP. Eligible studies included randomized controlled trials, controlled before and-after (pre-post) studies and meta-analyses. To generate the characteristics of the factors associated with VAP, the reported components of these trials were pinpointed and categorized. Results: A total of 14 papers were found that had investigated the factors linking enteral feeding and VAP. For these, 11 were randomized controlled trials, one was a meta-analysis and 2 were case-controlled analyses. The sample sizes varied from 10 to 2,528 subjects. Three major issues were identified based on the purpose of study interventions, and these were the effects of feeding method (continuous vs. intermittent), feeding site on aspiration (gastric vs. small bowel) and the timing of enteral feeding (early vs. late). Conclusions: Intermittent enteral feeding and with a small residual volume feed can reduce gastroesophageal reflux and increase total intake volume and early feeding can reduce ICU mortality. Nonetheless, the effects of these choices on preventing VAP still need further evaluation. A set of clinical guidelines based on these evidence-based findings with respect to enteral feeding is required, particularly one that covers all aspects of the enteral feeding process.