The adverse effects of excessive mobile phone (MP) use on children include deprivation from sleep, increased risk of lack of concentration, depression, anxiety and obesity. No such study has been conducted in children from Pakistan. Objectives: To assess the association of MP usage and musculoskeletal disorders in school going children. Methods: This was a cross sectional survey. Data were collected from different private schools of Karachi, Pakistan. Convenient non probability sampling technique was used. A sample size of 385 students was taken keeping a confidence interval of 95% with 5% margin of error. Results: A total of 385 subjects participated. It was also noticed that 75.6% (291) students have smart phone and 5.2% (20) have conventional phone and remaining 19.2% (74) have camera phone. It was noticed that the participants 306 (79.5%) said they slept for 1–2[Formula: see text]h daily and 30 (7.8%) had sleep for 3–4[Formula: see text]h daily. One hundred and four 104 (27%) had noticed pain in neck. Conclusion: The use of MP for any activity was associated with sleep deprivation and pain in wrist/hands followed by neck and upper back pain. The usage of MP should be limited to avoid the stress on musculoskeletal parts of the body.