An organic light-emitting display device includes a base substrate, a pixel array, a first power voltage wiring and a second power voltage wiring. The base substrate includes a pixel area and a peripheral area. The pixel array is disposed in the pixel area. The first power voltage wiring is disposed in the peripheral area and includes a first lower power voltage line and a first upper power voltage line. The first upper power voltage line is disposed on and contacts the first lower power voltage line. The second power voltage wiring is disposed in the peripheral area and includes a second lower power voltage line and a second upper power voltage line. The second upper power voltage line is disposed on and contacts the second lower power voltage line. The first upper power voltage line overlaps the second lower power voltage line in a plan view.