Lembaga Daya Dharma Keuskupan Agung Jakarta is a community that serves the poor and the oppressed living in Jakarta and its surrounding areas. One of the services that the community provides is by managing a credit union to teach the people to manage their finances more cleverly. The aim of this research is to make a computerized system so that data and information could be handled and communicated more quickly between credit union administrators using Microsoft Access. Presently, said administrators use Microsoft Excel to process data manually, and it takes a lot of time and manpower. System design will be done based on one of the methods in Systems Development Life Cycle, namely Prototyping, and it comprises of four stages. The first stage is the Planning stage, which consists of defining system requirements and carrying out a feasibility analysis. The second stage is the Analysis stage, which consists of establishing functional and non-functional requirements and behavior modeling. The third stage is the Design stage, and consists of designing the user interface. The fourth stage is the Implementation stage, during which the finished program is installed and tested for errors. In conclusion, a computerized system using Microsoft Access could be constructed, which is able to receive data input in relation to finances, members, and groups of the credit union. Financial reports, end-of-period reports, and statistical reports could also be displayed automatically.