A cargo toolbox is provided for securely retaining tools and equipment of varying size and shape, particularly suited for attachment to a vehicle and for use repairing fence lines. The toolbox comprises a lid hingedly secured to a base, a handle and latches for removably securing the lid to the base. A plurality of securement structures is disposed along the interior of the lid and base for storing and restricting movement of tools and components. Elongated tools may be stored within brackets disposed along the lid interior. Small items are separately retained within secure storage compartments disposed along an end of the base interior. A compartment lid is hingedly secured to the storage compartments such that items are prevented from departing. A restraining tray defining an upstanding wall perimeter and an open interior is mountable to a vehicle cargo rack to facilitate transportation of the toolbox.