Background: Respiratory diseases represent the most important cause of morbidity/ mortality in children. The present study was conducted to assess correlation of PEFR with age and BMI in children. Materials & Methods: 120 school children age ranged 10-15 years of both genders were included. Each child was subjected to measurement of peak expiratory flow rate. Child’s weight was taken with minimal clothes using electronic scale. Height was measured using standard stadiometer. BBMI was calculated with the formula - wt. (kg)/ [ht (m)2].