A method and apparatus for writing data to and reading data from a phase-change random access memory (PRAM) include encoding original data using a predetermined encoding function, selecting data, from among the original data and the encoded data, which require less power when being written to the PRAM, writing the selected data to the PRAM, generating marking information related to the selected data, and writing the marking information to the PRAM. Therefore, power consumption can be reduced when data are written to the PRAM.