Many risk factors related to HAP in the pts admitted at ICU consisted of age > 60 years old, operation, chronic obstructive pulmonary disease, coma, malnutrition, cigarette smoking, and having over 2 underlying diseases as well as intervention therapy such as tracheal intubation, repeat tracheal intubation, mechanical ventilation, tracheotomy, gastric intubation, sputum aspiration, brain surgery, and using PPIs, antibiotics, blood transfusion, and corticoides significantly (p<0.05).