A one-piece, cold-formed rocker arm of the cam follower type is provided. The rocker arm includes a one-piece metal body cold formed from a metal blank and being of U-shaped cross section substantially throughout its length. The body has a bottom wall with upstanding, structurally-integral side walls. An intermediate, convex portion of the bottom wall has a rectangular opening therein extending therethrough. A cam-contacting roller is rotatably mounted on an axle carried by the side walls above the rectangular opening. The roller has a circumferential surface positioned to engage a cam above the rocker arm. The rocker arm body has a downwardly-extending pin with a rounded end to receive a lifter post on which the rocker arm can pivot. The pin is affixed to the bottom wall at one end portion of the rocker arm body. The bottom wall has a shorter convex surface at another end portion with an elongate opening therein to receive an end of a valve stem.