This study examined the impact of Accounting Standards (AS) on financial performance of listed deposit money banks in Nigeria, specifically examined the trend in operating profit in the pre and post International Financial Reporting Standards adoption and also assess the impact of accounting standards on financial performance of the banks, The study population was fourteen banks as at 2021, and the sample size was thirteen (13) banks. Data were extracted from financial statements of the listed banks while tables, and line graph were used to determine the trend in real operating profit in the pre and post IFRS era, Multiple regression analysis was used to assess the relationship between Accounting Standard and financial performance. Study revealed that real operating profit was higher in the post IFRS adoption years, than that of the pre adoption years. Current Ratio revealed that significant relationship exists between accounting standards and financial performance with R2 of 0.187 and p-value was 0. 000. It was concluded that real operating profit was higher in the post IFRS adoption years, than pre adoption years. It was recommended that government should reduce inflation in order to improve the financial performance of the listed deposit money banks in particular and the national economy at large. Likewise, the government and the stakeholder should enforce the usage of IFRS in other to increase the financial performance of banks.

Keywords : Accounting Standards, Financial performance, Inflation, Real Operating Profit, Return on Assets, Return on Equity.