This paper aims to carry out an integrated Life Cycle Assessment to evaluate the environmental performance of retrofitting an existing first-generation ethanol plant for sustainable aviation fuel production. Two scenarios are defined, considering: (i) the incorporation of an alcohol-to-jet conversion pathway into a current bioethanol plant in Spain to produce synthetic paraffinic kerosene with aromatics biofuel, and (ii) the operation of two different plants, namely, an existing bioethanol production facility and a new-build ATJ plant. Results indicate that the global warming impact associated with the retrofitting of the bioethanol facility is 44.15 gCO2eq per MJ of final fuels produced. The main GHG impact is associated with the operation of both the cogeneration system (∼42 %) and the natural gas boilers (∼25 %) to cover the heat and power requirements of the bioethanol facility. Findings concerning the climate change impact of the new-build ATJ plant exhibit analogous behavior; the GHG impact is estimated at 44.53 gCO2eq/MJfuels. Future electricity supply mixes with high shares of renewables could lead to substantially lower GHG emissions (up to 61 %) in aviation fuel production, as compared to conventional jet fuels. The replacement of natural gas with sustainable alternatives could further decrease the global warming impact up to 97 %.