A method of registering phone book data, in a mobile communication terminal comprising a memory, a controller and a display unit, the method comprising: identifying that a request for displaying phone book data is input by a user; displaying a plurality of groups of phone book data stored in the memory on the display unit; selecting a group among the plurality of groups displayed on the display unit in response to user selection information; displaying on the display unit selectable phone book data items of the selected group which are read from the memory in response to identifying a request by the user; selecting at least one of the phone book data items displayed on the display unit in response to user selection information; identifying that the selection of the at least one of phone book data items is completed; if the selection of the at least one of the phone book data items is completed, identifying whether a group creation request is input by the user, by displaying an image on the display unit for asking the user whether to create a new group; - if the group creation request is not input, displaying on the display unit the plurality of groups, assigning a group, from among the plurality of groups displayed on the display unit, where the selected at least one phone book data item is to be moved in response to user selection information, and moving and storing the selected at least one phone book data item into the assigned group; - if the group creation request is input, requesting the user to input a name of a group to be created, creating a group having the input group name and moving and storing the selected at least one phone book data item into the created group. identifying that a request for displaying phone book data is input by a user; displaying a plurality of groups of phone book data stored in the memory on the display unit; selecting a group among the plurality of groups displayed on the display unit in response to user selection information; displaying on the display unit selectable phone book data items of the selected group which are read from the memory in response to identifying a request by the user; selecting at least one of the phone book data items displayed on the display unit in response to user selection information; identifying that the selection of the at least one of phone book data items is completed; if the selection of the at least one of the phone book data items is completed, identifying whether a group creation request is input by the user, by displaying an image on the display unit for asking the user whether to create a new group; - if the group creation request is not input, displaying on the display unit the plurality of groups, assigning a group, from among the plurality of groups displayed on the display unit, where the selected at least one phone book data item is to be moved in response to user selection information, and moving and storing the selected at least one phone book data item into the assigned group; - if the group creation request is input, requesting the user to input a name of a group to be created, creating a group having the input group name and moving and storing the selected at least one phone book data item into the created group. - if the group creation request is not input, displaying on the display unit the plurality of groups, assigning a group, from among the plurality of groups displayed on the display unit, where the selected at least one phone book data item is to be moved in response to user selection information, and moving and storing the selected at least one phone book data item into the assigned group; - if the group creation request is input, requesting the user to input a name of a group to be created, creating a group having the input group name and moving and storing the selected at least one phone book data item into the created group.