Abstract: A sink strainer assembly consisting of a body member of upright tubular shape having a lower portion connected to a drain and a larger upper portion joining to the lower portion so as to form a seat. A grid is mounted in the lower portion below the seat and a strainer basket is concentrically disposed within the upper portion. An upright plastic post is secured to said basket and a spring pressed ball member is mounted in the post so that it extends transversely outwardly at a position adjacent the lower end of the post. A resilient stopper secured to the bottom side of the strainer basket is movable into sealing engagement with the seat in a position of said post extending downwardly through said grid opening and with said ball engaging the underside of said grid so as to restrain upward movement of said post, and enable the stopper to be moved upwardly away from the seat by manual lifting of the post so as to cause the ball to be moved against the spring to a release position in the post.