The Masterplan II for IT in education launched by Singapore's Ministry of Education demands the adoption of a student-centred and constructivist oriented pedagogy. This study adapted the Knowledge Building Community (KBC) as a professional development model for teachers to develop the necessary competencies and beliefs for the reform. A computer-supported collaborative learning (CSCL) environment supports the adapted Teacher Knowledge Building Community (T-KBC). It is based upon social-cultural views of learning, recent theoretical developments in teacher education and adult learning theories. A qualitative case study approach was adopted to study the teachers' experiences of the T-KBC. Content analysis of the postings indicated that the teachers participated fairly actively in online knowledge building and they formed a socially cohesive community. The moderately sustained online discussion was developed to some depth. The teachers were interviewed for their beliefs about epistemology and pedagogy and these data were analyzed along with their reported experiences of the T-KBC. They reported a range of epistemological beliefs that varied along the relativist continuum. Their reported beliefs and practices of teaching and learning appeared to be related to their epistemological beliefs but they were mediated by their beliefs about the school contexts. The teachers' online participation fits their reported beliefs to some extent. Regardless of their beliefs, the teachers seemed rather satisfied with their learning and teaching experiences in the T-KBC. They reported changes in their views about students as knowledge constructors. However, they perceived that the time constraints caused by the curricula and the examinations would hinder them from implementing the reform. The findings apparently provide supports for emerging theories about learning, teacher professional development and claims about the affordances of CSCL. It seems that the T-KBC is a viable model for preparing practising teachers for the types of classroom learning that the reform is targeting. However, other systemic changes are needed.