A mobile terminal and a method of controlling the operation of the mobile terminal are provided. The method includes displaying an idle screen; if a communication event occurs, displaying an avatar image corresponding to a party of the communication event on the idle screen, the communication event including making or receiving a call and sending or receiving a call; and modifying the avatar image according to the amount of occurrence of the communication event. Therefore, it is possible for a user to easily recognize the occurrence of a communication event and the amount of occurrence of the communication event from an avatar image displayed on an idle screen.