The general argument of contingency theory reveals that there is no ideal or universal form for an accounting information system. Rather, the best choice of system is imposed by particular circumstances or contingencies. According to contingency theory, this study sought to identify factors affecting development of Management Accounting in Iran. Definitely, to accomplish this, current standing of Management Accounting in Iran should be studied first.Four categories of factors were recognized as affecting factors of Management Accounting development in Iran. As per Shannon's entropy these are ranked as follows: 1) Macro Environmental Factors includes legal, technological, accountability, economic and cultural factors; 2) Organizational factors includes size, culture, ownership, human resources, senior management, funding sources, penetration of management accounting knowledge within the organization, technology and structure of the Organization, 2) Attributes of management accounting practices includes Relative advantage, Complexity, Compatibility, Observability and Trialability. Worth noting that Organizational factors along with Attributes of management accounting practices ranked the same.3) Professional environmental factors includes localized management accounting software, presence of professional Management Accounting Associations, availability of Management Accounting Courses, availability of Management Accounting books and magazines and presence of professional management accounting code of conduct."Macro Environmental Factors" and "Professional Environmental Factors" affect on the "Organizational Factors". "Organizational Factors" and "Attributes of Management Accounting Practices" affect on the "Development of Management Accounting". The results of Management Accounting development are "Improving Activities and Business Processes, " "More Accurate Pricing of the Product", "More Accurate Product Costing" and... These are summarized as "Consequences of Management Accounting Development".