A method of programming memory cells of a resistive memory device includes; applying a first current pulse to each of the plurality of memory cells; applying a second current pulse that increases by a first difference compared to the first current pulse to each of the plurality of memory cells to which the first current pulse is applied; and applying a third current pulse that increases by a second difference compared to the second current pulse to each of the plurality of memory cells to which the second current pulse is applied, wherein the first through third current pulses non-linearly increase, and the second difference is greater than the first difference.