This is the first report of cactus virus X in Spain. It was found in dragon fruit (Hylocereus undatus) plants growing in an orchard, that showed mild chlorotic symptoms. The virus was identified following RT-PCR and Sanger sequencing of total RNA-extractions of symptomatic tissue. This also the first report of this virus in dragon fruits in Europe, and propagation of this emerging crop through planting of cuttings should include testing for this virus in order to prevent further spread.