OBJECTIVE: To study the status and influencing factors of malnutrition in rural children under 7 years of age in Gansu Province. METHODS: By stratified random cluster sampling, 9 390 rural children under 7 years of age from 4 counties of Gansu Province were enrolled. A cross-sectional investigation on children's nutritional status was performed. The major influencing factors of malnutrition were evaluated by logistic regression analysis. RESULTS: The detection rate of under-weight was 3.60% (338 cases). The growth retardation occurred in 992 cases (10.56%). Athrepsy was found in 196 cases (2.49%) out of 7 868 children under 5 years of age. Gender, age, birth weight, life style, parents' educational level and family income were influencing factors of malnutrition. CONCLUSIONS: More attention should be paid to the issue of malnutrition of rural children under 7 years of age in Gansu Province. The prevalence of malnutrition may be reduced through increasing family income and nutrition education, and improving parents' education level and children's life style.［Chin J Contemp Pediatr, 2010, 12 (12):950-953］