Aspiration pneumonitis is an important cause of many anesthetic and non-surgical deaths and complication. One hundred and eight cases from 1964 to 1974 were reviewed to study the factors associated with aspiration pneumonia. Forty surgical and 68 non-surgical patients were evaluated and compared. Predisposing factors included impaired consciousness, esophageal and neurological disorders, cardiac resuscitation, debilitation, presence of a nasogastric tube or tracheostomy. The most common findings in both groups were dyspnea, cough, cyanosis, fever, tachycardia, rhonchi, rales and wheezes. Sputa of 64 patients failed to reveal the precise etiologic agent. High mortality (30%) and morbidity were found in both groups even with optimum treatment. The causes of morbidity in both groups of patients were pneumonia, lung abscess, myocardial infarction, gastrointestinal hemorrhage, and pulmonary embolus. Prevention, with particular attention to high-risk patients and to factors influencing aspiration in groups of surgical and non-surgical patients, is the solution to the problem.