The preparation of ICT-Based materials is an integral part of teachers' daily learning and teaching processes. The aim of the study is to work with in-service teachers and a) determine their needs pertaining to ICT use, b) develop an in-service training program for improving their skills in terms of preparing ICT-based educational material c) to implement this program and d) to examine any improvement of teacher skills in this regard. The study has been conducted as action research and was carried out with a study group of 16 teachers. Findings obtained in the study revealed that teachers' scores on the TPACK-deep scale increased significantly compared to the pre-study. It was also shown that the in-service training activity that was carried out increased the knowledge and skills of teachers about current technologies that can be used in the learning-teaching process, as well as increasing their self-confidence and self-efficacy for developing ICT-based educational material. As they adopted the use of ICT-based educational materials prepared within the scope of in-service training during school courses, teachers have also been shown to report that students' interest, desire to participate, curiosity and excitement and motivation towards the lesson had increased. On the other hand, teachers who teach lessons with ICT-based educational materials stated that they felt their selves more useful in lessons, their performance increased, and that such materials facilitated the teaching in crowded classrooms.