The main purpose of this study was to evaluate the impact of professional development programs in teaching and learning process for primary school teachers. The study was conducted at Nyamagana District in Mwanza region. The participants consisted of the district education officer, chief inspector, five head teachers and fifty primary school teachers. Mixed research approach was employed using questionnaires, interviews and documentary reviews. Quantitative data was analyzed using computer software (SPSS) while qualitative data was analyzed by use of coding words. Data was then triangulated to find conclusions. This study had two major findings related to modes of professional development. According to the answers obtained from the respondents the models of professional development included; off-the job training and on-the-job training by means of further study and seminars. Some other findings include the use of student centered participatory method. Meanwhile, the challenges in professional development associated with funds, readiness of teachers, time and motivation. The study has implication for policy makers and primary school teachers. Policy makers should regard Professional Development Programs as part and parcel of improving quality of primary education. Policy makers have to enforce in-service training policy in order to accelerate for facilitation of professional development programs. On the case of primary school teachers, there should be enough funds set aside for supporting teachers‟ professional development programs and for buying studying materials from local initiatives. Conclusively, the world is changing and new technologies are becoming a potential in all sectors including education, therefore providing professional development program is inevitable.