Computers have occupied increasingly central roles in children’s world with the advance of technology. They have proved to be an ideal companion for children in developing and developed countries who spend most of their time at school or home with computers. As a measure of development and modernization, technology has made people’s lives easier and contributed positively to social well-being so far while it has also brought about some problems and threats stemming from irresponsible use of Internet. Unmonitored use of Internet may cause damages in children’s and young people’s physical, psychological, social and cognitive development. It seems imperative to assure that children and young people can benefit from computers and Internet resources effectively and productively while measures for appropriate and safe use of Internet are to be taken into serious consideration. Therefore, the government offices and institutions should lay stress upon the issue; education professionals and parents should be well-informed and regularly updated; and finally children and young people should be educated and monitored to achieve a better and efficient use of Internet. In this paper, has been mentioned to negative effect of internet usage on physical, psychosocial and cognitive health of children and young people.