Abstract: Objective To examine malnutrition and its influential factors among 0-3 years old children in rural areas of five provinces in western China.Methods The data on 30 495 rural children aged 0-3 years in five provinces in western China were collected from "Study on Physical Growth of Children under Seven Years Old in Rural Areas of Five Western Provinces,2006".World Health Organization child growth standard of 2006 was adopted as the reference standard.Unconditional logistic regression analysis was used to analyze the influencing factors of the children's malnutrition.Results The prevalence of stunning was 21.44%(23.61% for boys,19.23% for girls)and the prevalence of underweight was 15.96%(14.98% for boys,16.95% for girls).The prevalence of wasting was 7.44%(7.89% for boys,6.98% for girls).The multifactor analyses showed that gender,age,weight at birth,and feeding method within 4 months of age were influential factors of malnutrition.Conclusion The prevalence of malnutrition among the western rural children is high and probably influenced by the feeding in the first four months of age,family condition,birth condition,and children's physical condition.