OBJECTIVE: The double burden of undernutrition and overnutrition is recognized as a global devastating problem. However, few studies have investigated the maternal nutritional status among different ethnicities and the socio-demographic characteristics in rural areas of western China. This study attempted to fill this gap. DESIGN: Data on 10,495 women with children under three years old were collected using a three-stage probability proportion to size sampling from 45 counties of 10 provinces in western China. Generalized Estimating Equation (GEE) was used to assess the maternal nutrition conditions, including chronic energy deficiency (CED) and overweight/obesity. RESULTS: According to the WHO BMI standard, the prevalences of CED and overweight/obesity were 12.3% (BMI≤18.5 kg/m2) and 12.4% (BMI≥25 kg/m2), respectively, while overweight/obesity rate was 18.5% (BMI≥24 kg/m2) based on the Chinese standard. A significant difference in malnutrition between Han and Minority was not observed. The relationship between breastfeeding and CED was inverse (OR 0.64, 95%CI: 0.48, 0.87), but higher parity were positively correlated with CED (OR 1.57, 95%CI: 1.36, 1.82). The highest odds of CED were observed in the group with 1-5 years of education (OR 1.21, 95%CI: 1.03, 1.43). Higher parity was also associated with overweight/obesity (OR 0.78, 95%CI: 0.67, 0.91), and rural women aged 30-39 years old were more likely to be overweight/obese (OR 2.21, 95%CI: 1.47, 3.32). In addition, higher socioeconomic status was positively related to overweight women (OR 1.19, 95%CI: 1.01, 1.43), and inversely associated with CED (OR 0.83, 95%CI: 0.72, 0.97). CONCLUSION: The coexistence of undernutrition and overweight among women of reproductive age are determined in rural western China. It appears that socio-demographic factors considerably influence maternal nutritional status in the study. These findings have important policy implications for recommendations on maternal health intervention in China.