Abstract: Objective To study the nutritional status and its related factors among primary and middle school students in Hangzhou city and to provide evidences for the developing of nutritional intervention measures.Methods Totally 118 430 records of physical examination of primary and middle school students during 2009-2010 were extracted from the Management Information System of Health Monitoring and Early Warning for Hangzhou Students and multi-nominal logistic regression was adopted in the study.Results The proportions of malnutrition,low-weight,normal weight,overweight,and obesity were 13.0%,38.4%,27.9%,5.4%,and 15.3% among 61 645 male students and 10.3%,39.7%,37.0%,4.7%,and 8.3% among 56 785 female students,respectively.The distributions of nutritional status were different in general(Z_c=5.321,P=0.000) as well as in different growth periods(pre-puberty,middle puberty,late puberty,and early adolescence with Z_c values of -15.253,-20.938,-5.161,and -20.118,respectively,with significant differences between male and female students (P=0.000 for all).Male students were tend to have higher prevalences of overweight/obesity(odds ratioOR＝1.380,P=0.000)and malnutrition/low-weight(OR＝2.018,P=0.000)compared to the female students.The urban students were prone to get overweight/obesity(OR＝1.353,P=0.000)than the suburban students.Conclusion The proportion of low-weight was fairly high in primary and middle students of Hangzhou,and the prevalence of overweight/obesity was also high in the urban area.In addition,the male students were more apt to suffer from nutritional problems than females.Targeted measures need to be developed to improve the students' nutritional status.