An organic light emitting diode (OLED) display includes: a substrate; a first and a second thin film transistor (TFT) both disposed on the substrate and both having an active layer, a gate, a source and a drain electrode. A gate line is connected to the gate electrode of the first TFT, and a data line is connected to the source electrode of the first TFT. A common power source line is connected to the source electrode of the second TFT, intersects the gate line, and is parallel to the data line. A pixel electrode is connected to the drain electrode of the second TFT. An organic emission layer is disposed on the first electrode. A common electrode line is disposed on the organic emission layer. A secondary common power source line is formed with the same material as and is parallel to the common electrode line.