Many researchers critique that continuing professional development programs in Saudi Arabia are neither well organized nor are systematic. This study came to assess the impact of CPD opportunities in the country to better suit the professional needs of Saudi science teachers and support them in implementing the reformed instructional practices. Both quantitative and qualitative data were collected from 609 Saudi science teachers by means of closed and open ended questionnaire and later interviews with 9 teachers. Findings indicated that several Saudi science teachers have benefited from participating in the CPD programs but have also faced several challenges. Further analysis of the data resulted into five major themes; perspectives of participating in CPD, features of distinguished CPD programs, perceptions of ways to improve the impact of CPD, the impact of CPD on classroom practices, and barriers face classroom implementation.