Mobile phones have become an essential part of modern human life. They have many attributes which makes them very attractive to both young and old. There has been an increasing trend of use of mobile phones among students. Data has now started emerging with respect to the negative physical and psychological consequences of excessive use of mobile phones. There is need to increase knowledge of students regarding mobile addiction and its ill effects on health. Pre-experimental one group pre-test design was conducted to assess the knowledge of 8-16 years students in selected schools of Sangli - Miraj area. Total 70 samples were selected by simple random sampling method. A structured questionnaire of 15 items was administered to collect data. Planned teaching was given to the students regarding effects of mobile addiction on physical and mental health after the pre test. The pre test knowledge score was 8.77 whereas post test knowledge was 11.47. The planned teaching was effective in increasing the knowledge of students.