This research is entitled "Judicial Study of Joint Liability System Agreements in Savings and Loans Cooperatives (Study at PNM Mekaar Singosari Branch)". The research was conducted to determine the effectiveness of the Joint Liability System implemented in the PNM Mekaar Singosari Branch cooperative, and to determine the legal protection for cooperative customers if there are members who default. The research method used in this writing is a mixed research method, namely a mixture of sociological methods and normative methods. For the sociological method, this method collects data by conducting field studies, one of which is by interviewing to obtain information. Meanwhile, the normative method collects data through book sources related to what is being discussed. The aim of the thesis is to find out how PT Joint Liability System is implemented. PNM Mekaar which was carried out at the Singosari Branch, and found out how to resolve default cases among members of the PNM Mekaar group. The research results obtained show that with the implementation of the Joint Liability System which has been implemented at the Mekaar Cooperative Singosari Branch, group members or prospective group members must be ready to implement the Joint Liability System as a consequence of the regulations if they want to take out a loan collectively. This system requires shared responsibility, because in essence it is the community that determines the members of the group, not the Mekaar Cooperative, Singosari Branch. Before the disbursement of loan funds, PNM Mekaar will explain how the installments and joint responsibility system agreement will be implemented at the beginning. This is in accordance with the Civil Code Law and Law no. 25 of 1992 concerning Cooperatives. Even though the implementation of the Joint Liability System has become a solution to minimize the occurrence of defaults, there are still group members who are still in default in payment installments for PNM Mekaar Singosari Branch
