In a display apparatus, a light generating part generates a first light in response to a driving signal, and a first driving part outputs a panel driving signal. A display panel receives the first light from the light generating part and a second light externally provided, and displays an image in response to the panel driving signal. A light sensing part is disposed in the display panel so as to output a sensing signal corresponding a light amount of the second light. A second driving part compares the sensing signal with a predetermined reference value, and outputs a driving signal in accordance with the compared result. Thus, the display apparatus may reduce an electrical power consumed to drive the display apparatus.