Abstract: The invention concerns improvements in a split leaflet check valve. A pair of curved leaflets are hinged to a base ring for swinging movement from a normally closed position to an open position whenever a fluid is moving through the conduit wherein the valve is mounted. At the closed position, portions of each leaflet are seated upon the base ring and other portions are seated against each other to effect the closure. At the open position the leaflets, curved to the curvature of the conduit, lie against the sides of the passageway to provide for flow of fluid through the check valve with a minimum of turbulence. The hinge at the base of each leaflet is formed as a hook reaching into a side socket in the outer wall of the base ring. This check valve may be used where a minimal flow turbulence is desired such as in pipeline systems pumping sludge, artificial heart pumps and cardiac surgery.