In the past few years robbery of ATM card is increasing, in the present system pin number is used for ATM transaction security. which can be easily stolen, guessed or misused by many ways with this one can lose his money. This motivated us to increase user security by adding the biometric and OTP to the existing system. It also put forward some issues which include sensor durability and time consumption. And some queries like user lose how much if his card is misused? and to withdraw a low amount is it really admirable to go through the entire biometric process?. As a solution we introduce a constraint on transactions by ATM involving biometric(finger print) to improve the system performance and to solve the issues. We are adding a limit on amount of cash, if the entered amount is more than the limit, it is necessary to present biometric. If one need to withdraw the minimum cash, biometric scanning is not mandatory only will enter the OTP for user authentication. It help users to save time and maintain sensor performance by not furnishing their biometric for few hundred apart from maintaining security.