The article addresses the possible impact of utilising different accounting standards used in credit scoring on a client's internal credit rating. This impact is represented in the article by a change in the credit score achieved as a result of the application of data from financial statements compiled based on IFRS, in comparison with the values based on statements compiled under the Czech Accounting Standards [CAS]. The intention rests in identifying possible changes of a company's internal credit rating. The objective of this article is to demonstrate changes in the internal credit rating of a company, depending on the utilisation of the financial statements prepared under the Czech Accounting Standards and IFRS. When using data from IFRS statements in credit scoring, lower scoring values were obtained for the companies surveyed compared to the values that were found when utilising data from the financial statements compiled according to the CAS.