The modern political science concentrates on case studies of constituencies' boundary commission. Less attention has been paid to theoretical or even complex descriptive study of the phenomenon. To fill this gap, the present paper advances the first analysis of the institution of constituencies' boundary commission. This paper argues that these commissions are a unique institution regarding the method of forming, position in the system of governance, and the mode of operation. They solve specific administrative and political tasks in redistricting process, which cannot be performed by election commissions or other bodies. The institute of boundary commission is the only known mechanism to ensure the full participation of experts in the delimitation process. The commission is to ensure transparency in the delimitation process, public participation and political representation at a highest level. The presence of a constituencies' boundary commission corresponds to a high stage of development and institutionalization of the redistricting process. At the present stage the institute of boundary commission has become especially widespread in countries with the governmental model of electoral management. Another prerequisite for the implementation of these commissions is electoral system with the single member districts. The empirical relevance of the findings is tested making cross-case generalizations in 25 countries. It is conceivable that there are no institutional obstacles to implementing the constituencies' boundary commissions in the countries with "strong" election commissions.