ABSTRACT. Standard molecular methods for plant virus diagnosis require the purification of RNA or DNA extracts from a large number of samples, with sufficient concentration and quality for their use in PCR, RT-PCR, or qPCR analysis. Most methods are laborious and use either hazardous and/or costly chemicals.Apreviously published protocol for RNA isolation from several plant species yields high amounts of good quality RNADNA mixture in a simple, safe and inexpensive manner. In the present work, this method was tested to obtain RNA-DNA extracts from leaves of tomato, potato and three species of citrus, and was compared with two commercial kits. The results demonstrated that this protocol offers at least comparable nucleic acid quality, quantity and purity to those provided by commercial phenol-based or spin column systems and that are suitable to be used in PCR, RT-PCR and qPCR for virus and viroid detection. Because of its easy implementation and the use of safe and inexpensive reagents, it can be easily implemented to work in plant virus and viroid detection in different plant species. © 2016 Elsevier B.V. All rights reserved