According to one embodiment, a memory system includes a first memory, a second memory, a third memory, and a memory controller. The first memory includes a plurality of blocks. The second memory stores a first table having a plurality of first correspondences between a logical address and a physical address. The third memory has a higher processing speed than the second memory and stores a second table having second correspondences which are parts of the first correspondences. The memory controller determines whether data in a written block is first data to be copied, using the first table, not the second table. The memory controller copies the first data from the written block to a writable block to copy all data in a first state in the second block to the writable block. The memory controller sets all data in the written block to a second state.