The main purpose of this study was to design and implement a professional development program to support teachers' technological pedagogical content knowledge (TPACK) in a public education center in Turkey, and to evaluate impact of the program on teachers' TPACK. 10 teachers teaching adult learners in a public education center participated to this case study research. Data sources included teacher reflective reports, lesson plans and focus group interviews. The results revealed that the program enhanced teachers' TPACK and motivation to integrate technology into their teaching. The results emphasized the importance of giving active role to teachers in adult education centers and opportunities to design technology-enhanced learning artifacts working collaboratively in teacher teams.