According to one embodiment, a memory system includes first and second memory chips. The first memory chip has a first plane with a first block and a second block and a second plane with a third block and a fourth block. The second memory chip has a third plane with a fifth block and a sixth block and a fourth plane with a seventh block and an eighth block. The memory controller sets the first and third blocks as a first block unit in a user data storage area and the fifth and seventh blocks as a second block unit in the user data storage area. The memory controller allocates the second block, the fourth block, the sixth block, and the eighth block to a management data storage area. The memory controller manages user data operations for accessing the user data storage area in block units.