Provided are a thin film transistor (TFT) substrate and a display using the same. A TFT substrate includes: a substrate, a first TFT on the substrate, including: a polycrystalline semiconductor layer, a first gate electrode thereover, a first source electrode, and a first drain electrode, a second TFT on the substrate, including: a second gate electrode, an oxide semiconductor layer on the second gate electrode, a second source electrode, and a second drain electrode, an intermediate insulating layer including a nitride layer, on the first gate electrode, and an oxide layer covering the second gate electrode, on the intermediate insulating layer, on the oxide layer, and overlapping the second gate electrode, wherein the first source, first drain, and second gate electrodes are between the intermediate insulating layer and the oxide layer, and wherein the second source and the second drain electrodes are on the oxide semiconductor layer.