According to one embodiment, a memory system executes, when first address translation data including a first physical address indicating a physical storage location of the nonvolatile memory where data corresponding to a first logical address specified by a host is stored does not exist in a first cache and first compressed address translation data corresponding to the first address translation data exists in a second cache, an operation for storing uncompressed address translation data obtained by decompressing the first compressed address translation data in the second cache in the first cache and an operation for acquiring the first physical address from the uncompressed address translation data.