There are provided a DC-DC converter and an organic light emitting display device using the same. A DC-DC converter includes a converting module and a sensing unit. The converting module includes a switching module and a control module. The switching module has a plurality of switches, and each of the plurality of switches converts an input voltage into a first voltage and outputs the first voltage while being turned on/off in response to a corresponding pulse width modulation (PWM) signal. The control module controls a switching operation of the switching module by generating the PWM signal. The sensing unit senses driving current supplied to a load to which the first voltage is provided.