A semiconductor memory device has a single input terminal to select a buffer and includes input-output terminals, input-output buffers, a memory core, and a buffer selecting unit. The input-output terminals include address input terminals, data input-output terminals and an input terminal to select a buffer. The input-output buffers are coupled to the data input-output terminals respectively. The memory core is coupled to the input-output buffers through input-output lines. The buffer selecting unit generates a parallel buffer select signal based on an expected signal having a pulse stream, wherein the expected signal is provided via the input terminal to select a buffer in a test mode, and applies the parallel buffer select signal to the plurality of input-output buffers to select a corresponding input-output buffer. Hence, The semiconductor memory device may increase efficiency of a pin in a test device.