A simple, low-cost and sensitive UV sensor based on electrospun composite fibers was fabricated. Three different types of (PVA/ZnO) composites were used to fabricate the device. The solution-cast film of PVA and ZnO shows lower photocurrent than the other two fiber based devices. A comparative photoresponse study has revealed the high sensitiveness of the in situ derived composite fibers of PVA and ZnO under UV illumination thus making them highly suitable for the fabrication of UV detector. We believe that the coupled effect arising from the presence of PVA and uniform distribution of ZnO are responsible for the sensitivity of UV sensor. Thus we conclude that the response of UV sensor is highly dependent on the morphology of the composites and the preparation method. © 2012 Elsevier B.V.