The thesis shows how cell phones and the Internet affect the development of preschool children. The paper also presents the history of mobile phones, the Internet and other relevant electronic media, such as television and multimedia. It also shows the development of children and the positive and negative impacts of mobile phones and the Internet on the development of preschool children, and the impact of creative media use on children with developmental disabilities will be discussed. Excessive use of cell phones and the Internet can have a negative impact on the social development, emotional development, physical development and cognitive development of children. Long, excessive exposure to screens can cause problems with concentration, communication and social skills in children. Also, there is a danger of exposure to inappropriate content and developing addiction to the Internet and mobile phones at an early age of children. It is certainly important to ensure a moderate approach to the use of mobile phones and the Internet, with active monitoring of parents and educators and encouraging children to social interaction in real life, play and learning through physical activities.