Provided are a memory device for detecting a weakness of an operation pattern and a method of operating the same. The method includes: storing address information and activation count information regarding N word lines from among the plurality of word lines in a register including N entries; based on activation of a first word line different from the N word lines, storing address information and activation count information regarding the first word line in an entry from which information is evicted from among the N entries; and generating first weakness information based on a number of evictions performed on the register during a first period.