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This review of Life-Cycle-Analyses of biofuels synthesizes a wide range of questions raised by the increasing production of biofuels and by agendas aimed at boosting biofuels in future energy consumption. It also shows that current LCAs must be deepened or harmonized in some methodological aspects, and that they remain restricted in number as well as focused on only few North-American and West-European agro-industries. Expanding these analyses to other contexts, biomasses and agricultural modes of production would prove beneficial chiefly for two reasons: (1) there are almost no other ways of exploring and identifying sustainable reservoirs of bioenergies, (2) the LCA results turn out to be highly susceptible on the one hand to the agricultural techniques applied (motorization, chemical inputs, irrigation) in specific ecosystems (climate and soil types), on the other hand to arbitrations relating to the use of co-products (animal feed, soil enhancement, co-production of energy).