The invention relates to a check valve, particularly for sanitary water fittings, whereby preferably the valve closing member (11) is composed of a cone (4) and a cone cap (5), which is provided in the closing direction of the check valve with a dome-like attachment (12) wherein the valve closing member 98) of a pressure-relief valve is located, while the cone (4) has in the opening direction of the check valve a tubular extension (14) with a lateral inlet opening (13), the upper end of this extension forming a valve seat (15) for the valve closing member (8) of the pressure-relief valve (10), whereby this valve closing member (8) on its side facing away from the valve seat (15) rests on the top (16) of the attachment (12).