Abstract: Hydraulic tappet comprising a first and a second body shaped as a socket defining between them a chamber suited to be filled with a fluid coming from a source through an appropriate duct formed in the said socket bodies; along the said duct is arranged a ball for intercepting the fluid under pressure located in a corresponding conical seat formed in the bottom wall of the second socket and forming the outlet of the duct into the said chamber; in the bottom wall is formed an annular groove housing an elastic ring which partially occludes the said conical seat so as to allow a free movement of the ball inside the seat but not the exit of the ball from the seat.