A device and method for displaying image data and user interface (UI) data in a mobile terminal. A camera outputs captured image data to be displayed and a synchronous signal. The mobile terminal generates UI data. In response to the synchronous signal from the camera, a selector divides a frame data time into a first time and a second time. The selector selects and outputs the image data in the first time. The selector selects and outputs the UI data in the second time. A display unit displays the image data and UI data output from the selector on corresponding display areas.