The relationship between Rapid Automatized Naming (RAN) tasks and reading proficiency was first studied for English during the 70s, one finding being that children with dyslexia were slow and inconsistent in the RAN tasks. Later on, some studies have confirmed that RAN is the best predictor for transparent ortographies – and so of particular interest for Spanish. The research done so far on RAN and reading in Spanish is therefore reviewed here in order to draw conclusions for the diagnosis and treatment of reading difficulties. Our review shows that RAN is both a powerful early predictor of future reading outcomes and capable of discriminating between typical and poor readers. Being very easy to test, RAN is thus of great use in the diagnosis and prevention of reading disorders in Spanish.