Background and Purpose: Physical activity is the important source of development in children. As the smartphone use is strongly integrates in young people behavior it interrupts day to day activity due to which the physical activity is getting decrease in young population as they are getting more attracted to smartphones.The aim of the study is to see the effect of smartphone use on the physical activity in school going children. Subjects: Sample of 30 school going children is collected from the random population. Method: Participants were assessed for Brockport Fitness Test for the physical activity and the small version of smartphone addiction scale was used for the smartphone addiction rating. Result: The study results as smartphone addiction among the age group 11-17 years showed no significant effect on their physical activity. Discussion and Conclusion: Through the results it is suggested that subjects with smartphone addiction spend time using their smartphones on social media but along with that they also have good physical fitness.