Abstract: A static rubber sealing ring for sealing against fluids that have high temperatures and/or that are under high pressures, particularly for sealing between a cylinder lining and a cylinder block of internal combustion engines. With the intention of providing such a sealing ring that can advantageously replace the O-ring, particularly in such vibrating apparatus as piston engines, particularly diesel engines, there is proposed a sealing ring which includes a radially inner sealing surface (12) which is generally circular-cylindrical in shape at least when the sealing ring is fitted, and a pair of generally mutually parallel and axially opposing flat side surfaces (16), each of which extends generally at right angles to the radially inner sealing surface so as to define an edge (14) together therewith, and each of which connects with a gently rounded, radially outer sealing surface (22) of the ring via a transition surface (18, 20).