Abstract: A two piece oil control ring is provided which comprises a ring body (1) formed into a generally M- or I-shaped section with an annular groove (4) on an inside surface (3) of the ring body (1); and a coiled expander (2) attached in the annular groove (4) of the ring body (1) for resiliently urging the ring body (1) toward an inner wall of a cylinder. The ring body (1) is made of stainless steel that contains chromium of 3.0 to 13.0 weight % with the outer and inner circumferential surfaces (11, 12) covered with nitrided layers (14, 15). Circular ratio (&tgr;) of an outer edge length (Yo) to an inner edge length (Yi) in the cross section of the ring body (1) is in a range between 1.08 and 1.32 to keep precise peripheral circularity of the ring body so that the nitrided layers survive lapping of the ring body (14, 15).