The aim of the study is to measure professional development service quality and identify constraints, which the zonal education offices face when delivering quality professional development service to the teachers and principals in the Mannar zone. Data for the study was collected through the aid of questionnaires given to 299 teachers and principals from 20 different schools. Simultaneously semi-structured interviews were conducted with DDEs, ADEs and ISAs. Simple statistical techniques such as mean and standard deviation were used. The result reveal that the level of satisfactionof the teachers and the principals are moderate based on the responsiveness, tangibility and level of satisfaction. This study indicates that overall quality of professional department service is moderate as there are constraints such as lack of mechanism for identifying needs and monitoring the programme, lack of funds and commitment of the staff to provide quality professional service to the teachers and principals.