A method of and apparatus for varying a recording density of a data storage system. The method includes setting a range of a region whose recording density is to be changed, judging whether a region in which data read and write commands are to be executed is within the set range, and performing data read and write operations by allocating only one data among a plurality of continuous tracks as a data track if the region in which the data read and write commands are to be executed is within the set range.