the objectives of this study are to find the determinants of the profitability of Islamic and conventional banks listed in Qatar Exchange (QE) and investigate whether a significant difference between the two kinds of banks is existed. To achieve the research objectives, the researcher has collected the data from Bloomberg database and Central Bank of Qatar. These data have been analyzed by using Statistical Analysis Software (SAS). Descriptive statistics have been used to summarize and analyze the raw data, Correlation Coefficient analysis has been used to test the relationship between dependent and independent variables, and sample paired T-test has been used to test the difference of profitability between Islamic and conventional banks listed in Qatar exchange (QE). The independent variables that have significant relationship with the profitability of Islamic banks are; Loan deposit ratio (before and during the crisis), Capital adequacy ratio (before the crisis), Debt to equity (after the crisis), Debt to total assets (after), Asset utilization (during) Nonperforming loans to total loans (before), Non-performing loans to total equity (before), Bank size (before and after), inflation rate (during and after), Money supply (before and after), and Interest rate (before and after). The independent variables that have significant relationship with the profitability of conventional banks are; Loan deposit ratio (before), Capital adequacy ratio (before and during), Debt to equity (before and after), Debt to total assets (before and during), Operating efficiency (during), Non-performing loans to total loans (before and after), Non-performing loans to total equity (before and during), Bank size (before, during, and after), inflation rate (during and after), Money supply (before, during, and after), and Interest rate (before, during, and after). The researcher also found that there is a significant difference between Islamic and conventional banks during and after the crisis.