A method of displaying an advertisement on a display of a mobile communication terminal is provided. According to the method of displaying the advertisement, advertisement data is received through a wireless Internet network. The received advertisement data is compared with advertisement data stored in a storage device of a mobile communication terminal, to thus update the received advertisement data. It is determined whether the mobile communication terminal is activated and advertisement data to be displayed on a display of the mobile communication terminal is selected from the storage device according to the determination result. The selected advertisement data is displayed on the display of the mobile communication terminal.