Memory system

According to one embodiment, a memory system includes a semiconductor memory device and a controller. The semiconductor memory device includes a first memory cell arranged in a first region, and a second memory cell arranged in a second region. The controller is configured to control the semiconductor memory device. The controller is configured to: obtain first data based on a first read operation performed on the first memory cell, and second data based on the first read operation performed on the second memory cell; obtain third data based on a second read operation performed on the first memory cell, and fourth data based on the second read operation performed on the second memory cell, the second read operation being different from the first read operation in a read voltage; set a first value indicating likelihood of data stored in the first memory cell based on first information indicating that the first memory cell is arranged in the first region; in a case where the fourth data is equal to the third da