This paper presents the findings from a small-scale case study of Hong Kong primary teachers' perceptions of the factors affecting teachers' participation in continuing professional development (CPD). The study applies a multiple approach with mixed research methods, including using a self-developed survey questionnaire on the basis of the CPD framework as proposed by Advisory Committee on Teacher Education and Qualifications (ACTEQ, 2003) and focus group interviews with two groups of teachers. The study was conducted in two primary schools, in order to explore teachers' perceptions of the factors affecting teachers' participation in continuing professional development (CPD). The implications of school-based professional development and government policies related to CPD are discussed in the paper. (Contains 17 tables.)