The objective of this work is to study the quality of countable information before and after the adoption of standards IFRS. Precisely, through the exposure of the positive theory of the accountancy which insists on the importance of information of quality for the investors in order to enable them to make the adequate decisions of investments. We tested over one period being spread out of 1998 to 2008, the relation between the quality of the information measured by Proxy accruals qualityand standards IFRS in the context of the companies of CAC 40. The results obtained show that the adoption of standards IFRS makes improves quality of countable information. In particular, standards IFRS contribute improved quality information to diffuse it with the public and to increase his transparency, which makes it possible to attenuate asymmetries of information and the costs of agency.