An organic light emitting diode (OLED) display and a manufacturing method thereof, the OLED display includes: a substrate main body; a polycrystalline silicon layer pattern including a polycrystalline active layer formed on the substrate main body and a first capacitor electrode; a gate insulating layer pattern formed on the polycrystalline silicon layer pattern; a first conductive layer pattern including a gate electrode and a second capacitor electrode that are formed on the gate insulating layer pattern; an interlayer insulating layer pattern formed on the first conductive layer pattern; and a second conductive layer pattern including a source electrode, a drain electrode and a pixel electrode that are formed on the interlayer insulating layer pattern. The gate insulating layer pattern is patterned at a same time with any one of the polycrystalline silicon layer pattern and the first conductive layer pattern.