Abstract: A frame for an all terrain vehicle (ATV). The frame includes a bottom frame portion which has one or more bottom plates. Each of these plates is a sheet metal stamping with precision located mounting holes stamped into it for mounting vehicle components. The plates are secured to a pair of elongated reinforcing members oriented generally horizontally and generally parallel to one another along the length of the bottom frame portion. The bottom plates are of a length and width sufficient to shield a substantial portion of an engine and/or transmission mounted to the frame. The frame also includes a top frame portion and several structural support members supporting the top frame portion with respect to the bottom frame portion. Preferably at least some of the structural support members supporting the top frame portion with respect to the bottom frame portion are sheet metal stampings. In one preferred embodiment, one of the structural support members is a portion of the ATV's transmission.