Newly adopted plural unionism reveals many legal issues which need to be clarified. This essay discusses legal issues possibly arising out of procedures on the  decision for the bargaining representative union, which is made by the Labor Relation  Commission. The emphasis on main interests in the labor relation of our country is moving from the right to organize, which guarantees the establishment and activities of labor  unions, to the right to bargain collectively, which ensures the reasonable decision on  working conditions. It is necessary to have means to reinforce the collective bargaining  powers of many labor unions at the same time to decide working conditions reasonably. Procedures for determining the bargaining representative union is a system to  secure the basic labor rights pursued by our constitution to realize these purposes. The Labor Relation Commission’s assistances and supports are important for the amicable progress on procedures for determining the bargaining representative union. The Labor Relation Commission on procedures for determining the bargaining representative union will be involved in corrections on the public announcement of bargaining requests, corrections on the affirmative announcement of labor unions  with bargaining requests, decision on the majority of labor unions, organization of joint bargaining representatives, decision on the bargaining unit, and decision on whether  or not the duty of fair representation is violated among others. There are legal issues  for each procedure, which has been discussed. Common issues for each procedure were also discussed. Included are the decision  on jurisdiction, qualification of a labor union eligible for a party on procedures, whether  or not the Labor Relation Commission belongs to the applied descriptions for a party,  and interpretations on illegal and/or abusive rights for reasons of objections among  others. For the Labor Relation Commission to process matters relating to procedures for determining the bargaining representative union, it is necessary to make a decision  on jurisdiction above all and to define the concept of a business or workplace for such a purpose. The concept of a business or workplace refers to an organization equal  to a company. When there are a few workplaces across the country, the Labor  Relation Commission decides jurisdiction as it deems a case over the jurisdiction of two or more labor relation commissions in accordance with Article 3 of the Labor Relation Commission Act, where the main workplace is deemed as the one with the demand  for bargaining for the first time. In any procedure to process a case to decide procedures for determining the bargaining representative union by the Labor Relation Commission, any local or  branch of a labor union as a party without reporting on its establishment should be deemed as excluded. Although the local or branch carries out activities as an independent organization with its independent agreements and executive organizations, it should seemingly make a filing in procedures for determining the bargaining representative union under the name of an industrial union. The Labor Relation Commission shall freely make a decision on the contents in the texts for the decision without prejudice of filing details by parties. Although the reason of objections for the decision on procedures for determining  the bargaining representative union is limited to that of arbitration which violates law or is an act beyond its authority, the principle of laws for illegality and/or abusive rights as the reason of objections in the arbitration shall not be applied equally to any  dispute dealing not with profits but with rights. The introduction of the plural unionism and procedures for determining the  bargaining representative union is expected to fundamentally change the paradigm of orders in relationships between labor and employer not just because it changes  the structure of collective bargaining but because it affects other systems on the labor  union act and other labor related laws. Accordingly, it is necessary to sufficiently suggest  the interpretative aspects for the new system as soon as possible, together with the  precise suggestions on the interpretations on procedures to implement the system.