A centrifugal compressor impeller comprising: a gas inlet; a gas outlet; a disc having a plurality of blades extending therefrom, each blade being comprised of: a leading edge at said gas inlet; a trailing edge at said gas outlet; a blade base extending along said disc between the leading edge and the trailing edge; a blade tip extending between the leading edge and the trailing edge opposite said disc; a pressure side; and a suction side; wherein: the leading edge of each blade has a curved, convex or concave shaped, non-linear profile in the meridian plane; starting at said leading edge and for at least a blade portion, each blade has a first metal angle distribution at the blade base , a second metal angle distribution at the blade tip and at least a third metal angle distribution at an intermediate location between the blade base and the blade tip; and said third metal angle distribution is selected as a function of the non-linear profile of said leading edge such that in said intermediate location: - the blade has a double curvature with a concave surface on the pressure side and a convex surface on the suction side at least in a region adjacent the leading edge , in the case where the leading edge has a convex shape, and - the blade has a double curvature with a convex surface on the pressure side and a concave surface on the suction side at least in a region adjacent the leading edge , in the case where the leading edge has a concave shape. a gas inlet; a gas outlet; a disc having a plurality of blades extending therefrom, each blade being comprised of: a leading edge at said gas inlet; a trailing edge at said gas outlet; a blade base extending along said disc between the leading edge and the trailing edge; a blade tip extending between the leading edge and the trailing edge opposite said disc; a pressure side; and a suction side; the leading edge of each blade has a curved, convex or concave shaped, non-linear profile in the meridian plane; starting at said leading edge and for at least a blade portion, each blade has a first metal angle distribution at the blade base , a second metal angle distribution at the blade tip and at least a third metal angle distribution at an intermediate location between the blade base and the blade tip; and said third metal angle distribution is selected as a function of the non-linear profile of said leading edge such that in said intermediate location: - the blade has a double curvature with a concave surface on the pressure side and a convex surface on the suction side at least in a region adjacent the leading edge , in the case where the leading edge has a convex shape, and - the blade has a double curvature with a convex surface on the pressure side and a concave surface on the suction side at least in a region adjacent the leading edge , in the case where the leading edge has a concave shape. - the blade has a double curvature with a concave surface on the pressure side and a convex surface on the suction side at least in a region adjacent the leading edge , in the case where the leading edge has a convex shape, and - the blade has a double curvature with a convex surface on the pressure side and a concave surface on the suction side at least in a region adjacent the leading edge , in the case where the leading edge has a concave shape. <EOS>