According to example embodiments, a method of controller a memory system using a controller includes receiving a first read count command, determining if a read count of a non-volatile memory in the memory system exceeds a threshold value, and performing a first reading operation on the non-volatile memory according to the first read command. If the read count of the non-volatile memory exceeds the threshold value, then addresses are selected to which a plurality of additive reading operation corresponding to the first read command will be performed, in a random neighbor selection operation. The plurality of additive reading operations for checking data of neighboring pages of the page for performing the reading operation are distributed and processed.