The present disclosure relates to providing user information. In a method for requesting user information of an information requesting device in a mobile communication system, the method includes selecting a callee from a user, acquiring a user identifier (ID) of the selected callee, transmitting a user information request for the selected callee and the user ID to a relay server, evaluating whether an admission message is received from the relay server, and if the admission message is received, receiving user information from the relay server.