The conquest of the Eastern Balearic Islands by the Romans produced a profound transformation of the native communities and of their economic system. Whereas several aspects of the local economy at that period are well known, the changes experienced in the patterns of production and consumption of livestock still remain to be deciphered. By studying a series of faunal remains from the two main islands (i.e., Mallorca and Menorca), and focusing on the period spanning from the Iron Age to the Roman transition, we have approached the changes experienced in animal husbandry. Data from a large number of sites from both islands reveal the changes experienced in species composition and body size.