This essay examines the medieval Iberian translations of Greek works, a hundred titles which were rarely translated directly from their original language and, as usual in the medieval world, pieces that rarely transmit the name of the translator, although nearly 30 per cent name him. This corpus is examined dividing it into six subjects: spiritual life, philosophy, medicine and science, law, history and literature, seeking to understand the milieu in which they were produced, the reasons for the presence or absence of some titles in one or another of the Iberian territories, the public that demanded these translations, and their textual transmission to the present day. This comparative study shows us that in the fourteenth century all translations share cultural milieu and readers, and this situation changes in the second half of the fifteenth century, when in Castile versions are produced for the secular elite of the Court of John II (entertainment literature); neither in Portugal nor in Catalonia existed a similar milieu, where the works of a practical nature, philosophical, moral or spiritual reflection had an important presence (with a notable exception with regard to the Catalan version of Polybius, for example).