With the increased production of heavy and extra-heavy crude oils, and the need to add them into the regular diet to refineries, there has been much interest for developing new technologies for upgrading those heavy materials. Traditional commercially available carbon rejection and hydrogen addition routes are still applicable for this purpose, however they have shown some limitations when the oil is heavier, which directly impact in the economy of the technology. Various emerging technologies have been reported in the literature, mainly in patents, which have been developed and tested at different scale and with a wide variety of heavy petroleum. The most important emerging technologies for upgrading of heavy crude oils are reviewed and discussed. Particular emphasis is put in a comparison with the available information. It is recognized that all the technologies have great opportunity to be applied commercially depending on the support that they receive by the petroleum companies. (C) 2013 Elsevier B.V. All rights reserved.