In Indonesia there are still Muslim residents who have not used Islamic banking institutions as a medium for daily transactions and still use the services of conventional banking institutions whose transactions contain usury which is prohibited by Allah SWT. Meanwhile, the financial literacy level of the Islamic community is still quite lagging behind conventional literacy. This study aims to determine the effect of religiosity and Islamic financial literacy on customer decisions to use Islamic banking services. This research was conducted in the City of Payakumbuh to be precise on Islamic Bank customers who have savings and financing with a total sample of 96 people. The sampling technique in this study was using a purposive sampling technique with the type of quantitative research which was analyzed using SPSS Version 25. The results of this study are Religiosity has a positive and significant effect on the Customer Decision variable, Islamic Financial Literacy has a positive and significant effect on the Customer Decision variable, Religiosity and Islamic Financial Literacy simultaneously have a positive and significant effect on customer decision variables.