High blood pressure and its related problems are progressively assuming public health dimensions in developing countries like Bangladesh. There was a suggestion that hypertensive process can be aborted in its early stages. But it is poorly understood in its early stages. So, early natural history of hypertension and its evolution from the youth needs to be investigated. Objective of this study was to determine blood pressure distribution in school children aged 6-15 years. This descriptive cross-sectional study was conducted in the Department of Paediatrics, Mymensingh Medical College, Mymensingh, Bangladesh from November 2014 to October 2015. The sample was collected by simple random sampling from five different schools of Mymensingh after applying inclusion and exclusion criteria. After taking proper history and doing relevant examination, both systolic and diastolic BP was recorded by auscultatory method. Out of 994 children, 480(48.29%) were boys and 514(51.71%) were girls. In boys, the mean±SD of systolic and diastolic blood pressure (BP) were 105.9±10.8 mm of Hg and 67.4±6.7 mm of Hg and in girls it was 106.1±11.8 and 67.5±6.9 mm of Hg respectively. Systolic BP was found higher in girls belongs to 10-13 years. The study has shown that BP rises linearly with age and both systolic and diastolic BP has a significant positive correlation with age, sex, height and BMI in both sexes. This study also showed, 46(4.6%) children were hypertensive and 89(8.9%) were pre-hypertensive. Hypertension was found more in girls but there was no significant difference between two sexes. Hypertension was found more in relation to overweight, obesity and family history of hypertension. Hypertension is not uncommon in children. Routine blood pressure measurement should be conducted in all children.