The starting point of this study is the strong relationship among regional development, regional development agencies and participation concepts. The aim is to evaluate regional planning studies of regional development agencies who are the most important actors of regional development from participation perspective. Izmir and West Black Sea Development Agencies are selected as case studies, and indept interviews with members of regional development agencies and questionnaires with participants from different institutions (universities, firms, NGOs and etc.) and citizens were realized in order to reach the aim of the study. The results of all these indept interviews and questionnaires shows us, although they are relatively new institutions, Regional Development Agencies give importance to the participation in regional planning process, but in order to increase the effectiveness of the participation there are more works and regulations that have to be done.