A cargo container includes an outer aluminum housing having side, rear, bottom and top walls and a front opening with a pair of hinged doors. The housing receives a molded box-shaped composite outer shell which receives a molded box-shaped composite inner shell defining a cargo chamber. Corresponding walls of the inner and outer shells and the doors confine insulation cassettes each including vacuum insulation panels forming layers separated by a foam sheet and covered by corrugated plastic sheets, all wrapped with plastic film. Air is circulated within the chamber through a refrigeration evaporator and electrical heating elements, and a rear portion of the housing encloses a refrigeration compressor, storage batteries and a control system which senses the temperature within the chamber to operate the compressor and heating element from the batteries or an external power source to maintain substantially constant preselected temperatures within the chamber.