Abstract: A gate valve body having annular tapered seat rings retained in counterbores at inlet ends of an axial flow passage with the seating surfaces of the seat rings engageable by a tapered gate which is vertically guided by outwardly extending tongues on the gate slidably retained in grooves between laterally spaced pairs of guide rails on the body, the seat rings having a minor height less than width of the groove between the pairs of guide rails and an outer diameter greater than the lateral spacing between the guide rails, the seat rings being inserted into the associated counterbore by initially rotating the seat rings 90.degree.