Upper digestive feeding intolerance, as evidenced by high gastric residual volume and vomiting, is the most common complication among hospitalized patients receiving enteral nutrition. These patients are at high risk of developing aspiration pneumonia, which in turn is associated with prolonged hospital stay and increased mortality. Most episodes of aspiration are small in volume and do not lead to pneumonia. The likelihood of pneumonia increases with multiple aspirations. Pneumonia is also more common in critically ill patients who have bacterial colonization of the oropharynx. Gastric residual volume is commonly used as a means to assess aspiration risk during tube feeding. However, recent studies have demonstrated that this measurement has limited sensitivity. The approach to minimizing the frequency of aspiration during tube feeding involves assessment of the patient's degree of risk and initiation of appropriate measures directed at risk reduction.