In one example embodiment of the inventive concepts, an adaptive data backup method performed in a memory system including a non-volatile multi-level cell memory device includes receiving a write command from a host and determining a backup data size which is a size of data to be backed up among data requested to be written in the write command. The adaptive data backup method further includes selecting a backup type among at least two different backup types, based on the backup data size and backing up the data according to the selected backup type.