Chestnut (Castanea sativa Mill.) is a species used in Spain for nut and timber production. On the Canary Islands grafted chestnuts are planted in volcanic areas, where they show very good adaptation. On the four islands, Tenerife, La Palma, El Hierro and Gran Canaria, the local farmers identified 38 cultivars, of which 33 are different from the cultivars of the Iberian Peninsula. The inventory of Spanish cultivars now contains 212 cultivars, including these cultivars, with 23 cultivars being cultivated in two or more regions. Some of the cultivars from the Canary Islands, e.g. Arafero, produce large nuts. All the cultivars can be classified as marron type. Preliminary results with isoenzymes show an interesting variability between cultivars and also important intra-cultivar variability, as was found previously on the Iberian Peninsula.