In image sensors and methods of manufacturing the same, a substrate has a photoelectric conversion area, a floating diffusion area and a recess between the photoelectric conversion area and the floating diffusion area. A plurality of photodiodes is vertically arranged inside the substrate in the photoelectric conversion area. A transfer transistor is arranged along a surface profile of the substrate having the recess and configured to transfer electric charges generated from the plurality of photodiodes to the floating diffusion area. The transfer transistor includes a gate insulation pattern on a sidewall and a bottom of the recess and on a surface of the substrate around the recess, and a gate conductive pattern including polysilicon doped with impurities and positioned on the gate insulation pattern along the surface profile of the substrate having the recess, wherein a cavity is in an upper surface of the gate conductive pattern.