On the one hand, this article reviews the works presented on energetic analysis of Spanish agrarian systems since the 80's and, at the same time, we emphasize the originality and validity of those texts. On the other hand, we update to 2000 the estimates of the energy balance tor Spanish agriculture as a whole showing how the loss of energetic efficiency of agriculture has increased in the 90s. As a result of it, we have an agriculture with a growing and continuous dependence 01 energy, and not only due to the increasing use of machinery and fertilizers, but also because 01 the growing energy demand supported by electricity and petroleum, and related to the indiscriminate extension of the irrigable land with independence of the hydrological conditions of the territory.