Abstract: A down-hole oil well heater for improved recovery of oil includes a heating element comprising a sheet of electrically conductive paper which generates heat as a result of resistance to current flow therethrough and spaced apart, primary conductor elements preferably in the form of thin metal strips attached, as by sewing, to the conductive paper to provide uniform distribution of current flow through the paper from one conductor element to the other. Secondary conductor elements are electrically connected to said primary conductor elements and controller means are electrically connected to such secondary conductor elements for controlling the flow of electricity to the electrically conductive paper. The heating element covers a portion of conventional oil well tubing and is sandwiched between layers of electrically nonconductive, insulating material.