R. Camps, M. Castro, and X. Besoain. 2014. Simultaneous detection of CTV, CEVd and HSVd using Arizona 861 S1 Citron and RT-PCR. Cien. Inv. Agr. 41(2): 255-261. Citrus tristeza virus (CTV), Citrus exocortis viroid (CEVd) and Hop stunt viroid (HSVd) are pathogens that affect citrus trees in Chile. The simultaneous use of a rapid diagnostic method with the effective cleaning of infected budwood is a powerful preventative method for controlling viral diseases. The objective of this study was the multiple detection of CTV, CEVd, and HSVd, through bio-amplification in Arizona 861-S1 citron plants, combined with two incubation temperatures and multiple RT-PCR in two steps. Citron indicator plants were inoculated with the three pathogens, both individually and simultaneously, with four un-inoculated plants as controls. After four months of incubation at the two different temperatures, both the multiple and individually inoculated plants showed symptoms associated with these pathogens, which were subsequently corroborated through the use of multiple RT-PCR in two steps. This diagnostic method could be employed as an efficient, cost-effective alternative to the methods that are currently in use for detecting CTV, CEVd and HSVd, nevertheless its effectiveness should also be evaluated with tests using different isolates of these pathogens.