According to one embodiment, a controller of a memory system writes, in response to receiving from the host a write command specifying a logical address, data received from the host to a first write destination block. The controller manages a first list and first storage location information, the first list including a plurality of logical addresses corresponding respectively to write-uncompleted data, and the first storage location information indicating a storage location at a beginning of a write-uncompleted region in the first write destination block. In a case where a power loss has occurred without notice from the host, the controller writes the first list and the first storage location information to the nonvolatile memory using power from a capacitor.