Biofuels are nowadays considered a questionable environmental alternative to fossil fuels. In that context, this work analyses the environmental impacts when introducing rapeseed on the traditional and current wheat and barley agricultural rotation by means of a comparative life cycle assessment (LCA). The introduction of rapeseed, the correctness of its conversion to obtain straight vegetable oil and its use as self-consumption biofuel in tractors are evaluated. Life cycle assessment is used in this work to evaluate the impacts of different considered scenarios. A sensitivity analysis has also been conducted. The results presented show a modest environmental improvement (diminishment of 6 out of the 10 analyzed environmental impacts) when introducing rapeseed to local crop rotations and its partial conversion to oil to be used as fuel in existing diesel engines. Additionally, the ratio between the energy obtained and the total energy input shows moderate positive results when comparing the latter case with the current one. Results from this study can be used to support research and decision making to assess the convenience of introducing alternative fuels in agricultural exploitations. (C) 2012 Elsevier Ltd. All rights reserved.