In recent years, teachers’ professional development needs are quickly increasing for teachers’ being able to keep up with changing and development in information and communication technologies. When it is considered that teacher training process starts with pre-service training and continues with in-service training, and also transformations in every field of information societies, and aging pace of information are considered, validity of the information obtained in pre-service training process becomes a discussing issue. In this context, it comes into prominence that professional development activities should be planned lifelong. To provide teachers’ professional development needs effectively, efficiently and practically, teachers’ professional development activities should be based on adult learning theories. In this context, the purpose of this study is to present an analysis based on transformative learning theory in preparing in-service training activities in teacher training. At the end of the study, some practical suggestions were presented about integrating information and communication technologies into the teaching process within the scope of in-service training activities based on transformative learning theory.