The invention relates to a piston ring 1. Said piston ring 1 comprises an annular main body 2 which is preferably open at a butt joint and has a U-shaped cross section, the open side of which points inwards in the radial direction; an annular spring 4 which runs in the axial direction in a meandering manner and prestresses the main body 2 towards the outside in the radial direction; wherein meander loops 5 bear alternately against the limbs 3 of the U-shaped cross section in a section of the annular spring 4 which lies within the main body; and wherein meander loops 6 bear alternately against the radially inwardly pointing edges of the limbs 3 of the U-shaped cross section in a section of the annular spring 4 which protrudes out of the main body 2.