With more than 170 billion barrels of estimated oil sands reserves in Canada, Canada has the third largest oil reserves in the world. However, more than 80% of oil sand's reserves are located deep underground and could not be accessed by surface mining. Nonetheless, a number of in-situ recovery methods have been developed to extract heavy oil and bitumen from deep reservoirs. Once produced, bitumen is transferred to upgraders converting low quality oil to synthetic crude oil. However, in the present context, heavy oil and bitumen exploitation process is not just high-energy and water intensive, but also it has significant environmental footprints as it produces significant amount of gaseous emissions and wastewater. In addition, the level of contaminants in bitumen requires special equipment, and has also environmental repercussions. Recently, nanotechnology has emerged as an alternative technology for in-situ heavy oil upgrading and recovery enhancement. Nanoparticle catalysts (nanocatalysts) are one of the important examples on nanotechnology applications. Nanocatalysts portray unique catalytic and sorption properties due to their exceptionally high surface area-to-volume ratio and active surface sites. In-situ catalytic conversion or upgrading of heavy oil with the aid of multi-metallic nanocatalysts is a promising cost effective and environmentally friendly technology for production of high quality oils that meet pipeline and refinery specifications. Further, nanoparticles could be employed as inhibitors for preventing or delaying asphaltene precipitation and subsequently enhance oil recovery. Nevertheless, as with any new technologies, there are a number of challenges facing the employment of nanoparticles for in-situ catalytic upgrading and recovery enhancement. The main goal of this article is to provide an overview of nanoparticle technology usage for enhancing the in-situ catalytic upgrading and recovery processes of crude oil. Furthermore, the article sheds lights on the advantages of employment of nanoparticles in heavy oil industry and addresses some of the limitations and challenges facing this new technology. (C) 2014 Elsevier Ltd. All rights reserved.