A data compensation circuit and OLED display including the same are disclosed. In one aspect, the circuit compensates a voltage drop of a power voltage applied to a display panel of the display. The circuit includes an average current calculator configured to calculate an average current value of each of M×N pixel blocks. The circuit also includes a voltage drop calculator configured to calculate one or more pixel block voltage drops of the power voltage of each of the selected target pixel blocks based at least in part on an X-axis voltage drop and a Y-axis voltage drop of each of target pixel block. The circuit further includes an interpolator configured to interpolate the pixel block voltage drops of adjacent target pixel blocks so as to calculate a pixel voltage drop of a target pixel selected among one of the target pixel blocks.