We assessed the prevalence of anemia among schoolchildren in western China as determined by seven cross-sectional surveys involving 12,768 children aged 8-12 years. Subjects were selected randomly from 283 primary schools in 41 economically disadvantaged counties of Ningxia, Qinghai, Shaanxi and Sichuan Provinces. Data were collected through questionnaires and hemoglobin levels were measured. The anemia prevalence was 34% using the WHO hemoglobin cutoff of < 120 g/l. Boarding students and girls were more likely to be anemic. The prevalence of anemia in schoolchildren was high. Iron deficiency is a significant nutrition issue in China.