An automobile rear underbody structure which comprises generally elongated side frames extending in a direction lengthwise of an automobile body structure and each having a front and rear frame portions. The rear frame portion of each side frame lies in a level offset upwardly relative to the front frame portion. The rear frame portion has a depressed zone defined at a predetermined position thereof to permit the rear frame portion to bend downwardly when an external impact greater than a predetermined value is applied thereto.
