The fact that computers have had a profound effect on our life, motivates the introduction of computers into high school programs. Three main different ways of introducing computers into high school curricula, can be observed: computer literacy, the use of computers as a teaching aid in other disciplines, and computer science as a scientific discipline. No matter which way one chooses, teachers are crucial to the success of any program. Therefore, well trained teachers are needed. Computer science high school teachers must be qualified educators, but they also have to be knowledgeable in computer science. Their knowledge must be both broad and deep. This underlies the design of the computer science teachers' certification program suggested in this paper.