The invention relates to a cotyloid component of a hip
prosthesis, said cotyloid component being hollow and in the form of a cup whose outer part has a thread allowing it to be fixed in the
iliac bone, said thread being a discontinuous self-
cutting double thread (20, 21), and said cotyloid component having a flattened upper pole (1), a
coating that promotes
osseointegration on its outer face (10), and a concave, substantially hemispherical and polished inner surface (11), characterized in that: (a) the
pitch of the threads (20, 21) decreases from the upper pole (1) towards the equatorial periphery (3) of the cotyloid component, (b) the thicknesses of the threads (20, 21) increase from the upper pole (1) of the cotyloid component towards its periphery (3), (c) the crest of the threads (20, 21) is sharp towards the pole (1) of the cotyloid component and rounded or substantially trapezoidal towards the equatorial periphery (3) of the cotyloid component.