Acetabular prosthesis comprising an acetabular cup, an acetabular insert, able to be stably coupled inside the acetabular cup and configured to receive an articulation head and a centering unit configured to guide and center the insertion and stable positioning of the acetabular insert in the acetabular cup. The centering unit comprises a centering hole provided in the acetabular cup and a centering pin provided on the acetabular insert and which develops along a centering axis, configured to be inserted in the centering hole. The centering pin is provided with an external lateral surface that has an undulating development along the centering axis.