Abstract: A pressure regulating valve with a push pull adjusting knob includes a valve body housing a valve member defining an annular seat adapted for engagement with a knife edge seat on a valve sleeve insert. The valve member is opened and closed by a flexible diaphragm operating mechanism, the diaphragm being exposed on one side to outlet valve pressure and on its opposite side to the atmosphere and a valve control spring. A valve stem rotatably mounted in a valve bonnet adjusts a valve nut for varying the compression of the spring, and thereby the spring force on the diaphragm. A push-pull adjusting knob slidably and rotatably engages the valve stem. The knob is locked against the bonnet in one axial position and is released from the bonnet in the opposite axial position for rotating the valve stem. A detent between the valve stem and adjusting knob provides resistance to the adjusting knob movement, and knob movement is limited by a cap threadably engaged with the end of the adjusting screw.