The carbon footprint of crop fertilization has been estimated in Spain and its provinces in the long term (1860-2018). To carry out this work, a detailed database has been developed with information on the management of nitrogen fertilization in 122 rainfed, irrigated and greenhouse crops for 50 provinces. The upstream and downstream emissions of the system have been estimated considering the differences between Mediterranean and temperate climates as well as the evolution of efficiency in fertilizer manufacturing.