A double-sided cutting insert comprising: opposing top and bottom surfaces (32, 34) and a peripheral side surface extending therebetween; wherein: the peripheral side surface comprises at least two opposing major side surfaces, each of which has at least two distinct relief surfaces, each relief surface defining a major cutting edge with the top or bottom surface (32, 34); the peripheral side surface comprises two opposing minor side surfaces, wherein the two opposing major side surfaces are joined via the two opposing minor side surfaces; the cutting insert generally has 180° rotational symmetry about a first axis extending through the opposing top and bottom surfaces (32, 34) and 180° rotational symmetry about a second axis extending substantially perpendicular to said first axis; a through-bore extending axially along the first axis; a transition surface extending between the top and bottom surfaces (32, 34); wherein the relief surfaces are inclined at a clearance angle (μ) with respect to the first axis, in a cross-sectional view; and wherein the relief surfaces of each major side surface are inclined in different directions; characterized in that the two relief surfaces are joined via, and merge at, the transition surface. opposing top and bottom surfaces (32, 34) and a peripheral side surface extending therebetween; wherein: the peripheral side surface comprises at least two opposing major side surfaces, each of which has at least two distinct relief surfaces, each relief surface defining a major cutting edge with the top or bottom surface (32, 34); the peripheral side surface comprises two opposing minor side surfaces, wherein the two opposing major side surfaces are joined via the two opposing minor side surfaces; the cutting insert generally has 180° rotational symmetry about a first axis extending through the opposing top and bottom surfaces (32, 34) and 180° rotational symmetry about a second axis extending substantially perpendicular to said first axis; a through-bore extending axially along the first axis; a transition surface extending between the top and bottom surfaces (32, 34); wherein the relief surfaces are inclined at a clearance angle (μ) with respect to the first axis, in a cross-sectional view; and wherein the relief surfaces of each major side surface are inclined in different directions; characterized in that the two relief surfaces are joined via, and merge at, the transition surface. the peripheral side surface comprises at least two opposing major side surfaces, each of which has at least two distinct relief surfaces, each relief surface defining a major cutting edge with the top or bottom surface (32, 34); the peripheral side surface comprises two opposing minor side surfaces, wherein the two opposing major side surfaces are joined via the two opposing minor side surfaces; the cutting insert generally has 180° rotational symmetry about a first axis extending through the opposing top and bottom surfaces (32, 34) and 180° rotational symmetry about a second axis extending substantially perpendicular to said first axis; a through-bore extending axially along the first axis; a transition surface extending between the top and bottom surfaces (32, 34); wherein the relief surfaces are inclined at a clearance angle (μ) with respect to the first axis, in a cross-sectional view; and wherein the relief surfaces of each major side surface are inclined in different directions; characterized in that the two relief surfaces are joined via, and merge at, the transition surface.