Corsica is a privileged site for citrus growing due to its special phytosanitary status. This Mediterranean island is free of naturally transmitted European quarantine diseases tristeza, mal seco, stubborn and vein enation wg, and exotic quarantine diseases. The San Giuliano citrus repository was founded in 1958 with the aim of gathering the best cultivars of citrus and submits them to a selective indexing procedure for eliminating individuals affected by graft transmissible diseases. This phytosanitary selection program, jointly developed by CIRAD-FLHOR and INRA was gradually initiated for elite citrus individuals from Corsica, Morocco and Algeria. Furthermore it was extended to other citrus growing areas of the world by the technique of nucellar selection and subsequently by the procedure of shoot-tip grafting which enlarged the collection to include monoembryonic species/cultivars. The sanitation technique is combined with highly sensitive detection tools based on susceptible indicators, serology affinity or nucleic acids specificity. This repository is unique in that accessions are maintained in orchards as disease-free adult trees. It allows a morphological description and a control of pomological performance. The phytosanitary status is controlled regularly all along the different processes and surveillance by periodic visual checks is made in the outdoor nuclear stock plots. A copy of the newest and the most interesting accessions is maintained under screenhouse. There are presently more than 450 scion varieties and almost 140 seed source trees varieties from 33 citrus growing countries available at San Giuliano, and also individuals of related genera belonging to Citreae. Besides phylogenic and evolutionary considerations, genetic assessment under the EGID system adopted by FAO, provides potential for careful management of citrus resources within a general scheme of varietal improvement. Furthermore, this programmer constitutes a basis for the Citrus Natio