Assessment of nutritional status by using BMI showed that 28.1% of inpatients was undernutrition (24.2% at internal medicine departments, and 32.4% at surgery departments); Some risk factors for undernutrition of inpatients were old age (≥ 60 group was higher than <60 (p <0.001), smoking (smokers were at higher risk than patients used to smoke and nonsmokers (p<0.001); living place (patients who live in rural areas had a 1.6 times higher risk of undernutrition than those living in urban areas (p<0.001).