This cross sectional study was conducted to measure the PEFR values of normal school going children of Mymensingh, Bangladesh. Peak expiatory flow rate (PEFR) is a lung function test which is easily measurable and reproducible but the base line values of PEFR have not been studied in large scale among Bangladeshi children. In Mymensingh municipality out of 79 schools 4 schools were selected purposively. A total of 984 (499 boys and 485 girls, nearly equal in ratio) normal children (6-15 years), were selected randomly by using lottery technic in classroom. To obtain peak expiratory flow rate (PEFR) mini Wright peak flow meter was used. The highest of three readings was taken as the correct value. Anthropometric parameters including body weight and height were recorded by bathroom scale and stadiometer respectively and body surface area was calculated. According to age interval (10 months) in boys and girls the mean difference of PEFR values showed that among age categories of 6, 7 & 8 years had no significant (p were <0.18, <0.73 and <0.70 accordingly) and all other age categories the mean difference of PEFR between boys and girls had significant (p<0.01). The correlation coefficient (r values) and the level of significance between different anthropometric parameters and PEFR in case of boys and girls were significant (p<0.001). Correlation of height (boys r=0.961 & girls r=0.954) with PEFR was the highest in comparison to other anthropometric parameters (age, sex and body weight). Boys had significantly higher values of PEFR than the girls at any height.