A novel toilet seat cover is provided herein. The cover comprises a water-impermeable, very light weight, easily disposible paper, the paper being in the form of a porous paper coated only on the reverse side thereof which is adapted to face the toilet bowl with a water-repellent material, thereby retaining a porous paper surface for contact with the user while rendering the paper as a whole water impermeable and non-porous, the paper being provided with a single central straight line longitudinal slit opening or a perforation or line of weakness. The toilet seat cover is folded longitudinally along the slit or perforation and then is folded transversely in a zig-zag or back-and-forth accordion-type fold to be folded at least for the region of the slit or perforation. The toilet seat cover, when in use, is adapted to be placed over the toilet seat and to have its peripheral edges folded under the toilet seat to be retained thereby. Further, by the sole application of body pressure by the user, the toilet seat cover is thus adapted to be made to fit a toilet seat opening automatically. The toilet seat cover may be dispersed in the form of individual folded seat covers or in the form of a seat cover detached from a roll of a plurality of identical seat covers. Thus, with the present invention, the entire sheet is placed on the toilet seat, and the peripheral edges then folded under the toilet seat so that the cover may be retained thereby. Then, by the user sitting on the cover, the slit or perforation automatically extends and expands to provide the optimum opening.