As has been well documented, the written word has been a fundamental vehicle for the transmission of Reformed theology in the Italian peninsula. Yet books were only part of the process of spreading heterodox doctrines. It was the oral word, and above all the preached word from the pulpit, to plough the soil on which the written word took root and flourished. Focusing on the 1540s, the article tries to address on the one hand the theme of the increasingly sophisticated rhetoric and the concealment abilities used by preachers to escape ecclesiastical control, and on the other hand the measures taken by ecclesiastical authorities to face these new challenges.