The county Assembly is governed by Migori County Assembly Service Board (CASB) established pursuant to section 12(1) of the County Government Act 2012 as a Body corporate with perpetual succession.

It has Five members and the Clerk: 

1. Hon. Speaker of the Assembly as the Chairperson; 

2. Leader of Majority as the Vice Chairperson; 

3. Leader of Minority

4. The fourth and the Fifth Member who are persons resident in the County appointed by the County assembly from among persons who have knowledge and experience in Public affairs, but who are not members of the County Assembly . Preferably they are appointed with consideration of both genders, Male and Female

The Clerk of the Assembly is the Secretary to the Board.

The statutory mandate and responsibilities of the Board Include:-

1.Providing services and facilities to Ensure the efficient and effectives functioning of the County Assembly;

2.Constituting offices in the County Assembly Service and appointing and Supervising Office holders;

3.Preparing annual estimates of expenditures of the County Assembly services and submitting them to the county Assembly for Approval and exercising budgetary control over the service;

4.Undertaking singly or jointly with the other relevant organizations, programs to promote the ideas of Parliamentary democracy;