According to one embodiment, a semiconductor memory device includes a first memory cell capable of storing 3-bit data. When first data including a first bit is received from an external controller, the received first data is written to the first memory cell. When second data including a second bit and a third bit is received from the controller after the first data is received, the first bit is read from the first memory cell and the 3-bit data is written to the first memory cell based on the read first bit and the received second data. In the 3-bit data written to the first memory cell, lower bit data is determined by three read operations, middle bit data is determined by two read operations, and upper bit data is determined by two read operations.