Using of the internet today is a growing part of any society. Teenagers are the most users of the internet at their home and/or school. Therefore, it changes their daily lives in terms of physical, social, and psychological status that may exaggerated to be an internet addiction disorder or a physical problem. The aim of the study was to recognize the effects of excessive internet use in Saudi and Egyptian teenagers' health. The design used to conduct the present study was a descriptive correlation design, a convenient sample of 668 teenagers who were recruited from intermediate and secondary school from both countries, 331 teenagers from King Saudi Arabia (KSA) and 337 from Arab Republic of Egypt (ARE). Three tools were used for data collection: the first one was a questionnaire including demographic background of the participants and their families. The second was Internet Addiction Test (IAT) Young (1998) and the third pain rating scale to assess the intensity of musculoskeletal pain that encountered by the students. Results show that 86.6% of KSA teenagers used the internet daily compared to 69.6% in ARE. Regarding internet addiction, in teenagers, 0.9% were severe, 45.3% moderate and 47.7% mild compared to 0.3%, 46.3% and 44.2% in ARE one, 67.3% of KSA teenagers have musculoskeletal pain with internet usage compared to 74.3% in ARE teenagers. No significant relation was found between both groups in relation to internet addiction. A significant relations were found in Saudi students' socio-demographic data and their level of internet addiction in the area of academic level (p ≤ .001), and level of academic achievement (p = .037). No significant relation was found in the same area for Egyptian students. The researchers suggest further studies to be conducted in this field on larger sample size for both genders to identify the other factors related to excessive internet use.