According to one embodiment, a memory system includes a non-volatile memory and a controller. The non-volatile memory is configured to store an address translation table and a data map. In a case where an invalidation command for invalidating the data written in the non-volatile memory is received from the host, the controller is configured to update the address translation table and the data map based on the invalidation command. A response to the invalidation command is transmitted to the host after the address translation table is updated and before the data map is updated.