In several countries biodiesel blending programs have been implemented looking for reduction in fossil fuel dependence and environmental benefits, including climate change mitigation. Currently global biodiesel produced from different fatty raw materials, about 6 billion liters annually, represents 10% of whole biofuel production. Nevertheless, in many cases the actual advantages of biodiesel production and use are not clearly evaluated. Essentially, the feasibility of biodiesel production can be determined by its efficiency in solar energy conversion, as indicated by agro-industrial productivity and energy balance parameters, which expresses the relative demand of natural resources (land and energy), to produce biofuel. Taking into account the Brazilian conditions, in this paper an assessment of biodiesel production is presented, comparing four different productive systems. According to this evaluation, soybean and castor are limitedly feasible, whereas tallow and palm oil represent more suitable alternatives. The proper selection of an efficient productive system is crucial for rationality of biodiesel production.