Abstract: A screw with anti-loosening means, which includes a securing element with a ring portion and that can be inserted about a shaft of the screw under a head thereof and, with the screw in a state in which it is screwed on a base, prevents the screw from being turned back counter to a screwing-in direction. The securing element has on the ring portion, on a side facing the surface of the base, at least one projection which can be pressed into the surface when screwing in the screw. The securing element can have an outer circumferential region of the ring portion, with finger-like extensions which, with the securing element in the inserted state, extend along the circumference of the head and under spring-elastic forces of the securing element, contact a surface structure of the body that has an inhibiting action counter to the screwing-in direction.