Abstract: An underlift attachment for tow trucks is attached to a tow truck by initially cutting a vertical slot in the tailboard of the tow truck's housing. A pocket member is welded in the slot flush with the tailboard, and a pivotable boom arm is mounted to pivot between a storage position journaled within the pocket, and a working position extending generally horizontally rearwardly from the tow truck. The tow truck's tow cable is extended from the tow truck's boom through the pulley hook and connected to the boom arm to raise and lower it between its storage and working positions. The boom arm of the attachment includes an extensible telescoping arm journaled within a boom arm housing, and is provided with a pivotal cross bar. The extensible arm is connected to a hydraulic cylinder which will extend or retract the telescoping arm and the cross bar. Attachment brackets are slidably mounted on the ends of cross bar and serve to hold the axle of a vehicle, or the like, for towing.