The purpose of this study was to investigate the standardization of height growth curves of 8 ethnic groups in Thailand and Union of Myanmar. The height of 16,000 children from 5 to 18 years old of 8 ethnic groups, i. e., Thai, Karen, Hmong, Lisu, Akha, and Lahu in Thailand, Burmese and Mon in Myanmar, was measured from 1994 to 2004 in Thailand, from 2005 to 2008 in the Myanmar. Modified BTT model was applied to height growth curve, and the fluctuation of standard deviation was smoothed using weighted moving variation and smoothing function developed by the authors. Finally growth charts were obtained using z-score of normal distribution. Resultant growth charts were generally satisfactory and were seemed to be useful from the perspective of data utilization. Though there are a few problems on the growth charts such as variance was decreased for more than 15 years old, or height growth has continued till 18 years old in some ethnic groups. Representing heights were different more than 10 cm among ethnic groups at 18 years of age. It was confirmed that it is important to create a growth chart by ethnic group respectively and utilize it in order to evaluate properly the growth status and the nutritional condition of the children.
