In light of the liberalization of the global financial markets, the technological development and the growing phenomenon of globalization, the banks resorted to the use of basic financial instruments, and with the expanded use of these tools, there is a need to audit how to use them. Therefore, the study aimed to determine the relationship between the determinants of auditing financial instruments and the effectiveness of external auditing through a field study on a number of Egyptian banks as an example for Egyptian banks through the use of a survey list directed to academics and external auditors in audit offices. And distributed the number (110) list, and the percentage of the correct lists 78%, The study found that there was no significant difference between the opinions of the academicians and the external auditors on the relation between the determinants of (adherence to the rules of the Central Bank, the extent of adherence to professional issues related to financial instruments, the adequacy of auditing standards in reducing the risks of financial instruments, The forecast gap in the auditing of financial instruments, the development of the auditor's report to reduce the risks of financial instruments and meet the needs of its users) and the effectiveness of external audit