This chapter introduces the challenges and opportunity of biooil and the technologies available to produce and refine it into value added products. In the introduction, this chapter presents the economic potential of biooil via technoeconomic analysis to compare with conventional fuels via minimum fuel selling price, as well as the availability and characteristic of some common biooil-producing biomass feedstocks. Later, it explains about the two common technologies to produce biooil, namely pyrolysis and hydrothermal liquefaction, and the key parameters affecting the outputs and yields. Lastly, this chapter also lists the quality and testing standards from ASTM International for biooil to be utilized as burner fuel to facilitate in commercialization and marketing. © 2022 Elsevier Inc. All rights reserved.