An apparatus and method for inputting a character using a keyboard displayed on a touch screen in a portable terminal. The apparatus and method determines if a touch signal is generated, with the keyboard displayed. Upon generation of the touch signal, a touched character is recognized by analyzing the touch signal. The character is displayed enlarged in a predetermined screen area. It is then determined if the touch has been completed, while the character is displayed enlarged. Upon sensing the touch completion, the character is displayed in a main screen area.