A display device includes a buffer connected to a data line of a display panel, a bias-mode verification unit which generates a bias-mode signal based on an nth image data signal and an mth image data signal (“m” is a natural number smaller than “n”) corresponding to the data line, a data selecting unit which selects one of a plurality of bias enable signals having different duty ratios from one another based on the bias-mode signal, a control signal generating unit which generates a switching control signal based on the bias enable signal selected by the data selecting unit, and a bias control unit which applies, to the buffer, at least one of a plurality of bias control signals having different levels from one another in an output period defined by the switching control signal.