Lowest Cost Cargo Transport Act of 1983

Lowest Cost Cargo Transport Act of 1983 - Amends the Merchant Marine Act of 1936 to require that all government-generated cargoes be transported at the lowest cost and whenever possible at the lowest landed cost. Requires Federal agencies to establish a competitive bidding system for the transport of such cargo. Directs the General Accounting Office, within 36 months of enactment of this Act, to review such system and report to Congress on its findings and recommendations.

Requires that U.S.-flag vessels transporting government-generated cargoes or export shipments financed by the U.S. not exceed 25 years of age or be substantially rebuilt and certified as having a useful life of at least five years after such rebuilding. Makes an exception to the requirement that 50 percent of government-generated cargo be transported on U.S.-flag commercial vessels from specified geographic areas, when such vessels are unavailable.