We report on room temperature electroluminescence from an inorganic/organic heterojunction light emitting diode based on ZnO nanowire arrays. The heterojunction is fabricated by depositing the p‐type polymer poly(3,4 ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) on n‐type ZnO nanowires grown by electrodeposition on transparent conducting glass (ITO) substrates. The nanowires are encapsulated in a thin polystyrene film deposited from high‐molecular‐weight solution. Electron injection occurs through the transparent ITO layer while hole injection is mediated by the PEDOT layer and gold contacts. The current–voltage (I–V) characteristics of the device shows a diode‐like behavior. A broad emission spectrum covering most of the visible range and reaching to the near ultraviolet is observed at voltages between 6 and 8 V under ambient condition. The device operation is stable for more than 5 h.