Thermal methods are inevitable in heavy oil/bitumen recovery. Different types of "aqueous" methods such as cyclic steam and hot water injection, in-situ combustion, hot water and steam flooding, and steam assisted gravity drainage have been widely applied over decades. Currently, non-aqueous heating methods, generally named electromagnetic, are in consideration as an alternative to the aqueous methods, which may not be applicable due to technical and environmental limitations. This technique still requires further research and field scale pilot applications to prove their technical and economic viability. In this paper, a critical discussion on the review of electromagnetic heating is presented. An attempt is undertaken to review most of the research works (computational and experimental as well as a limited number of field applications) performed over more than five decades. After evaluating aqueous and nonaqueous thermal methods, a comparative analysis is presented. (C) 2015 Elsevier Ltd. All rights reserved.