Sumber indah aluminium store is a trading business that provides a wide range of aluminum materials, aluminum accessories, acrylic, and aluminium composite panels (ACP). In addition to providing aluminum materials sumber indah aluminum store also serves aluminum processing for building construction and household needs. Accounting information systems are an important part of a company. In carrying out its business activities sumber indah aluminum store has implemented a manual and komputer-based accounting information system. An effective accounting information system will have a good impact on a company's success in the long run. Therefore, the authors conducted a study with the title Comparative Analysis of The Effectiveness of Komputer-Based Accounting Information Systems in The Sumber Indah Aluminium Store which aims to compare the perceived effectiveness when implementing komputer-based accounting information systems. This research uses qualitative research method with data collection techniques through interviews and supported by documentation. The research was conducted with interviews with informants who are authorized in using accounting information systems at sumber indah aluminium stores. The informants interviewed by the authors are store leaders, business managers, and financial employees. Based on the results of this study the authors obtained the results that komputer-based accounting information systems are more effective than accounting systems before komputer-based.