Abstract: A rod guide apparatus for a reciprocating rod comprised of two substantially identical half sections which include semicircular recesses therein and which are adapted to be lockingly clamped together adjacent opposite sides of the outer periphery of the rod whereby the rod extends through a bore formed by the semicircular recesses in the half sections. By the present invention each of the half sections includes at least one longitudinally extending ridge on a surface thereof within said semicircular recess whereby when the half sections are clamped together adjacent opposite sides of the rod, the ridges are positioned on opposite sides of the rod and deform the bore formed by the recesses through which the rod passes into a cross section of elliptical shape so that the clamped together half sections contact the periphery of the rod at at least four points thereby preventing slippage of apparatus on the rod.