The present invention relates to a method of classifying and storing the call durations of a mobile communication terminal and, more particularly, to a method of classifying and storing call durations, which classifies call durations, call time categories, etc. related to calls with calling partners stored in the address book of the mobile communication terminal, so that the user can recognize his or her call pattern and control the amount of call traffic, thus efficiently utilizing the mobile communication terminal. When an incoming or outgoing call is started, a calling partner of the call is identified, and a timer is operated to count call duration. When the call is terminated, the timer is stopped, and the actual call duration with the calling partner is calculated, thus classifying the call duration. The classified call duration is stored in the information area according to the calling partner of the call.