Abstract: A check valve having a removable seat portion with integral flapper (valving means) is disclosed. The seat portion can be removed through a port in the valve body without breaking any connection of the valve body to the associated fluid flow lines. The seat portion can comprise two sections that secure between them sealing means (e.g., an O-ring) for creating a fluid tight seal when the valving member of the check valve is closed against the seat portion. A fluid tight seal is created between the valve seat portion and valve body by tapers on the valve seat that cam against corresponding recesses of the valve body to force the valve seat portion against the valve body.