This study examined the impact of an intensive professional development series on early childhood educators' content knowledge of engineering and their self-efficacy towards teaching engineering. Seventeen early childhood teachers participated and responded to questionnaires, surveys, and focus-group interviews before and after the professional development. The results show that these early childhood educators significantly (1) increased their knowledge of engineering; (2) improved their engineering teaching self-efficacy; and (3) enhanced their confidence level towards teaching engineering for young children. This study is important because it provides an example of an effective approach to enhance early childhood teachers' preparation in teaching engineering activities for young children. It also sheds light on the urgency to improve overall teacher preparation and continuous education in science, technology, engineering, and mathematics for young children.