Abstract:The article investigates the notion of transport biofuels, their possible advantages and disadvantages in comparison to traditional fossil fuels, and sustainability requirements that need be stated to their quality and production methods from a legal perspective. The research results indicate that the understanding of what makes the quality and production of transport biofuels sustainable is still unclear. Sustainability parameters for biofuels will differ depending on the types and purposes of biofuel production. There is no clearly agreed definition on what biofuels, and particularly sustainable biofuels are. The task of law in this situation can be to contribute to the sustainable production of biofuels through the use of the traditional and newly emerging legal approaches and instruments, such as e.g. sustainability criteria for biofuels in Directive 2009/28/EC.