Abstract: An anti-extruding packer for pressurizing under fluid pressure a segment of pipe or the connection between a segment of pipe and a coupling comprising: a cylindrical body member having a central bore and a reduced diameter portion at one of its ends, thereby defining an annular shoulder, a plurality of spaced apart protrusions depending from the annular shoulder, an annular groove provided in the annular shoulder and ring segments mounted on the annular shoulder and matingly engaging the protrusions for preventing the extrusion of the packer in the direction of the flow of the fluid under pressure.