Abstract The spread of biofuels has generated controversy at international, national and regional levels due to the environmental, economic and social impacts that its production and consumption can cause. Recently, the Spanish government has been promoting the production of biodiesel in industrial plants located in Spain and other EU countries. These developments are expected to stimulate the cultivation of rapeseed in the EU to the detriment of extra-EU imports of biodiesel mainly based on soybean oil from Argentina, which has been one of the main suppliers of biodiesel in Spain for years. As a result, the environmental impacts produced throughout the life cycle of biodiesel consumed in Spain could be radically affected. In this context, the environmental impacts of biodiesel produced in Spain and Argentina with rapeseed cultivated in Spain and soybean cultivated in Argentina were compared under certain growing conditions using life cycle assessment (LCA). Consequential and attributional approaches were compared under the ReCiPe method to test potential biases. The results showed that the biodiesel produced with Argentinean soybean oil had fewer environmental impacts than biodiesel produced with Spanish rapeseed oil. Seed production (and fertilization) was the process (and sub-process) that generated the greatest environmental burdens, and it is an area in which improvement is necessary in order to increase sustainability, particularly with regard to Spanish rapeseed-based biodiesel.