Due to the importance of spreading computer science education among young people, we present in this paper our work in preparing and organizing a computer science competition for children from 8 to 15 years old, named Kids programming marathon, the marathon goes in three phases and targets all kids in the country, tasks of the marathon are divided into three different types, each type is intended to support different skills for children, we show our motivation and goals of the marathon, we present the process of the marathon in details and show the materials of the competition, how it was chosen and how it is used in the tasks, we show some statistics, and finally discuss the impact of the marathon on the society, and our view for the future of this competition.