BACKGROUND/OBJECTIVE: The objective of the study was to provide current estimates of the prevalence and trends of overweight and obesity (OW+OB) in Mexican children and adolescents. SUBJECTS/METHODS: Body mass index objectively measured was analyzed for 37 147 children and adolescents aged 0-19 years obtained in 2012 as part of the National Health and Nutrition Survey (ENSANUT-2012), a nationally representative sample of the Mexican population. In addition, data from previous National Nutrition Surveys obtained in 1988, 1999 and 2006 were compared with analyze trends over a 24-year period (1988-2012) for children <5 years of age and adolescents and over a 13-year period (1999-2012) for school-age children. World Health Organization Child Growth Standard was used to define OW+OB. RESULTS: In 2012, 33.5% of children <5 years of age (both sexes) were at risk of overweight or were overweight (OW); 32% and 36.9% of girls and boys 5-11 years of age were OW+OB, respectively, and 35.8% and 34.1% of female and male adolescents were OW+OB, respectively. Statistically significant trends were documented for all age groups during the study period. Overall change in the combined prevalence in preschool children was 6.3±1.0 percentage points (pp; P<0.001; 0.26 pp per year) in the last 24 years, showing the highest increase between 1988 and 1999, whereas for school-age girls (from 1999 to 2012) and adolescent females (from 1988 to 2012), OW+OB increased across all periods at a declining trend, with an overall change of 0.5 and 1.0 pp per year, respectively. Changes in the prevalence of OW+OB were highest among children and adolescents in the lowest quintile of the household living condition index. CONCLUSIONS: Prevalence of OW+OB among children and adolescents increased significantly during the last 13-24 years. The rate of increase has declined in the last 6 years in all age groups. Changes in prevalence of OW+OB presented here suggest that, in Mexico, the burden of obesity is shifting toward the groups with lower socioeconomic level.