Objective: To determine the breast-feeding pattern of four main ethnic groups (the Han, Uygur, Tibetan and Zhuang) living in rural western China. Design: The study utilized a cross-sectional design. Setting: Forty-five counties in ten provinces in western China in 2005. Subjects: A sample of 11 783 children younger than 36 months old (8960 Han, 1281 Uygur, 792 Tibetan and 750 Zhuang) and their mothers were recruited using a stratified, multistage, cluster random sampling method. Results: The rates of exclusive breast-feeding of children at 6 months of age in the Han, Uygur, Tibetan and Zhuang ethnic groups were 11·6 %, 0·8 %, 4·4 % and 13·8 %, respectively. The rates of any breast-feeding for children at 24 months of age were 8·5 %, 25·7 %, 3·0 % and 4·3 % in the four ethnic groups, respectively. After adjusting for related factors, Zhuang children had a higher odds ratio of exclusive breast-feeding to 6 months compared with Han children, whereas Uygur and Tibetan children had lower odds ratio (Zhuang: OR = 1·291; 95 % CI 1·006, 1·657; Uugur: OR = 0·062; 95 % CI 0·032, 0·121; Tibetan: OR = 0·323; 95 % CI 0·220, 0·475). Uygur children had a lower hazard ratio of discontinued breast-feeding compared with Han children, whereas Tibetan children had a higher hazard ratio (Uygur: HR = 0·368; 95 % CI 0·333, 0·408; Tibetan: HR = 1·366; 95 % CI 1·244, 1·500). Conclusions: The breast-feeding pattern differed among the Han, Uygur, Tibetan and Zhuang ethnic groups. The results suggest that health education regarding the benefits of breast-feeding is needed in rural western China.