Objectives　To explore the impact of high body mass index (BMI) on irritable bowel syndrome (IBS) in Chinese adolescents. Methods　The students were randomly selected from middle school and high school. They completed the epidemiological questionnaire of IBS and had their height, body mass measured. Results　In total, 1173 students were recruited, including 700 middle school students and 473 high school students. The incidence of overweight/obesity was 30.52%. The incidence of overweight/obesity was not significantly different between boys (28.40%) and girls (32.65%) (P=0.114), and there was not significantly different between students from middle school (30.57%) and high school (30.44%) (P=0.963). Two hundreds and twenty-one students suffered from IBS and the incidence of IBS was 18.84% with no significant gender difference. The incidence of IBS was significantly higher in students from middle school (13.43%) than those from high school (26.85%) (P<0.001). The incidence of IBS was not statistically significant between overweight/obese students (22.07%) and normal weight students (17.42%) (P=0.061). The distribution of IBS subtypes had no statistical significance between overweight/obese and normal weight students (χ2=0.91，P=0.823). Conclusions　Overweight/obesity and IBS were extremely prevalent in Chinese adolescents, but the correlation between them remains to be confirmed.