Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 44 1 2015 01 15 36 42 Lu Ma Dept. of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University , Guangzhou, China. Yanna Zhu Dept. of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University , Guangzhou, China. Jincheng Mai Guangzhou Health Care Clinics of Middle and Primary Schools , Guangzhou, China. Jin Jing Dept. of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University , Guangzhou, China. Zhaomin Liu Dept. of Medicine & Therapeutics, The Jackey Club of School of Public Health and Primary Care, Chinese University of Hong Kong , Hong Kong. Yu Jin Dept. of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University , Guangzhou, China. Li Guo Dept. of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University , Guangzhou, China. Yajun Chen Dept. of Maternity and Child Health Care, School of Public Health, Sun Yat-Sen University , Guangzhou, China. 2015 10 14 Background: No studies have been reported on children obesity prevalence of Guangzhou, one of the most urbanized areas in China. This study tracks the secular trends of obesity prevalence of children. Methods: The data were derived from the surveys on students’ constitution and health carried out by government. Randomly, 3832 students in 2007, 13141 in 2008, 14052 in 2009, 13750 in 2010, and 15225 in 2011, aged 7-12 years, from urban primary school were examined. Anthropometric parameters were measured in all students. Results: The mean of body mass index increased significantly from 16.6 in 2008 to 16.8 in 2011 in the total group of children, and the total prevalence of overweight and obesity increased from 9.4 and 6.2 to 10.5 and 7.5 from 2007 to 2011, respectively. The minimum value of the mean body mass index and the overweight and obesity prevalence in the total age group all appeared in 2008. The prevalence of overweight and obesity in males was significantly higher than that in females in each year among the 5 years. Conclusion: Although the prevalence of children obesity in Guangzhou in 2011 is still lower than the average values of Chinese large coastal cities, a significant increase was found in their prevalence from 2007 to 2011 and the total obesity prevalence of children is even higher than that of adolescent. Furthermore, we found that the minimum value of overweight and obesity prevalence of the total group and almost all gender-specific age groups appeared in 2008. https://ijph.tums.ac.ir/index.php/ijph/article/view/3730 https://ijph.tums.ac.ir/index.php/ijph/article/download/3730/3403