Abstract: There is disclosed a hip prosthesis to replace a damaged hip-joint. The hip prosthesis is intended to be disposed at one end thereof into a cup-shaped cavity of an acetabulum and at the other end thereof into a femur canal of a person suffering from a damaged hip-joint. The hip prosthesis comprises an acetabulum part having a cotyloid member to be tightly engaged into the acetabulum, an elongated neck part, and a femur part. The elongated neck part has an articulation head at one end thereon, the head being shaped to be articulately received in the acetabulum part, and a slidable connection at the other end thereof for engagement with the femur part. The femur part has a femur canal insertable portion formed with an arrangement to secure same in the femur canal by being embedded in regenerated bone marrow, and an engaging channel to receive the slidable connection of the elongated neck part and to securely connect the elongated neck part to the femur part.