Investigations were dedicated improvement of oxidative stability of vegetable oils and their derivatives, using both synthetic antioxidants and obtained plant extracts. Carried out improvement of biodiesel quality and searching of it byproduct (raw glyceride, fatty acids, mono-, diglycerides) utilization. Compositions of biodegradable lubricants - chain saw oils and hydraulic oils were formed. Vegetable oils grown in Latvia - rapeseed, lineseed, hempseed, sea buckthorn oils, waste oils and tallow were used in investigations. Possibilities of chemical modification of triglycerides - transesterification, epoxydation, ozonolysis, production of estolides and estolide esters were investigated. Possibilities of synthetic transformation of glycerine - synthesis of monoglycerides, glycerine acetates acetals and ethers were investigated.