This study sought to describe the benefits and challenges of adopting computerized accounting information systems emphasizing internal control aspects. The specific objectives of this study were: identifying the internal control benefits of adopting CAIS, assessing the challenges of using CAIS concerning input, process, storage, output, and personnel controls, and also assessing the relationship among IT knowledge, IT governance, and computer fraud. To realize the research objective, 10 NGOs were selected using purposive sampling. The study followed a parallel convergent mixed-method design with a descriptive research approach. 112 informants comprising auditors, finance heads, and IT officers participated in the study with a response rate of 90%. Structured interviews were conducted with 10 experienced professionals. The study extensively reviewed works of literature and empirical studies to support the finding. The finding of the study indicated that adoption of CAIS involves internal control benefits as well as challenges. Improvements in internal control are achieved through the use of extra protection provided by the systems such as password and data authentication. Accountability and compliance are also reported to have improved due to use of CAIS. Human related data control challenges were identified. Data input, storage and access challenges were reported to be the major challenge areas. IT governance and IT knowledge are indicated to contribute towards computer fraud detection and strengthening of internal control of organizations. It is hence recommended that managers as designers and implementers of internal control systems should work on the application of IT governance and update employees' IT knowledge on a regular basis. The result of the study is believed to provide insights to accountants, managers, auditors, IT auditors, information system professionals, academicians, government, and regulatory bodies.rnKeywords: Computerized accounting Information Systems, CAIS, AIS, internal control, computer fraud, IT governance, ITG, IT knowledge, Information Technology, IT, Ethiopia