This chapter deals with some important aspects of deoxygenation of triglycerides that has become a new refining technology. After the introduction of basics of deoxygenation chemistry, the thermodynamic aspects of deoxygenation are discussed. Then hydrodynamics in conventional hydrotreaters is compared with the deoxygenation system, and predictions on the vegetable oils deoxygenation are made. Kinetics of triglyceride deoxygenation reactions including kinetics of the individual reaction steps involved are discussed for the system CoMo on alumina. Next factors influencing catalyst deactivation, particularly those related to feedstock, are analyzed. Finally, commercial, available deoxygenation technologies are overviewed. The attention is focused on both stand-alone and coprocessing technologies.