Abstract: A ball valve seat is provided which comprises two separate reinforcement members, preferably of metal, embedded in an annular resilient body. The interior of the resilient body defines at one end a part-hemispherical ball valve seat and at its other end, of greater wall thickness, an outlet controlled by the ball valve. One of the reinforcing members has a flared skirt extending into the narrower wall thickness end of the resilient body and a narrower neck located in the wider wall thickness end of the resilient body, where it is received in an annular groove in the second reinforcement member. A portion of the second reinforcement member extends within the wider wall thickness end of the resilient body radially of the first reinforcement member over its skirt portion.