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The calls of the Blue-fronted Amazon (Amazona aestiva) are described and their possible function within the social organization of the species during breeding and non-breeding seasons are discussed. We identified 9 vocalizations; six ('wak-wak', 'wa-wawawa', transitions, 'gu-gugu', guturals, 'ka-kaka') were nonspecific and were given in several circumstances: alarm, contact, feeding, and flying. The remaining had specific contexts: 'waahh' (agonistic), 'grr-uip' (contact in flight), and songs (reproduction-territorial). Vocalization rates increased in alarm contexts and during the non-breeding season, probably as a result of increasing interactions between individuals. The frequency containing the greatest amount of energy was a useful variable to characterize Blue-fronted Amazon calls, particularly at the species level. The most commonly used vocalization, 'wak-wak', has structural features that promote directionality and short-range transmission, enhancing its usefulness for the aggregation of individuals. It is suggested that songs were derived from a process of repetition and increasing variability from gutural calls. The highly contextual variability of these calls may be due to an incompletely specialized repertoire or a vocal system based upon combinations of calls for conveying messages., The Blue-fronted Amazon (Amazona aestiva) is a parrot whose distribution extends over northeastern Brazil, Bolivia, Paraguay, and northern Argentina (Forshaw 1977, Darrieu 1983). Populations have declined in recent years, especially [...]