The evaluation of the internal controls over financial reporting is a difficult task which has to be learned over the years. Experience is a good teacher in this respect. So, education guided by experience may be expected to be fruitful. The purpose of this paper is to model, implement, and validate a knowledge-based system, called the "Auditor"s Report on Internal Controls over Financial reporting" (ARICOFR), that is capable of formulating the opinion on the effectiveness of internal controls over financial reporting, as expressed in the auditor"s report on internal controls over financial reporting. The main research questions studied in this study are: (1) can ARICOFR carry out the task of evaluating the internal controls over financial reporting equally as may be expected from an experienced auditor? If so, (2) how should ARICOFR be constructed and validated? And (3) to what extent is ARICOFR effective, efficient, and acceptable as a tool to help auditor evaluate the effectiveness of internal controls over financial Reporting? The knowledge used by ARICOFR is developed from the literature, and from qualified auditors through questionnaires and in-depth interviews. After putting into practice, the knowledge base is presented to experienced auditors for review. The ARICOFR performance is confirmed by test cases. From the consequences of the confirmation, we may conclude that ARICOFR is fruitful in performing the task of evaluating the internal controls over financial reporting. : البحث ملخص