A method for detecting a leakage current in a bit line of a semiconductor memory is disclosed. In one embodiment, the method includes isolating the connection of a sense amplifier from a bit line via an isolation transistor, reading out a memory cell to the bit line, waiting until a predetermined delay time has elapsed, so that a leakage current measurably changes the voltage on the bit line within the delay time. The sense amplifier is short circuited with the bit line via the isolation transistor. The voltage on the bit line is collected by the sense amplifier, and compared with a reference voltage so as to detect the leakage current.