Middle East countries have begun to implement economic reforms to stimulate private investment, promote economic growth and support the transition to market economy. Although, it is difficult to define the direct impact of the accounting system reform on economic transformation, as there are many other conditions that have influence on the transition process. However, with the central position of financial reporting and control in the economic system based on market economy, it is reasonable to assume that countries that are more effective in reforming the accounting system would move faster toward economic transformation. This paper examines the value relevance of accounting information in Saudi Arabia for the period 1993-2008, before and after revising national accounting standards, which could express effects of reform in national accounting standards by The Saudi Organization for Certified Public Accountants (SOCPA). The results obtained from a combination of regression and portfolio approaches, show accounting information in Saudi Arabia stock exchange is value relevant. A comparison of the results for the periods before and after reform, based on both regression and portfolio approaches, shows an improvement in value relevance of accounting information after the reform in accounting standards. It could be interpreted to mean that reform of the national accounting standards improve relevancy of accounting numbers in the Saudi Arabia stock exchange.