The Italian iconography of the doctor saints Cosmas and Damian reflects fluctuations in the fortunes of the cult of those saints with significant variations in appearance and meaning being tied to changes in the position of the saints with respect to function, as miraculous healers, as representatives of professional doctors and as patrons of a powerful family. This study considers the development of the iconography of the doctor saints Cosmas and Damian in Italy, beginning with the emergence of images in the late antique period. These early representations are explored within the context of the historic and liturgical origins of the cult of SS. Cosmas and Damian with particular attention paid to the hagiography and more specfically the miracle stories which provide a significant amount of information about the role of images in a Christian healing cult. Evidence that sheds light on the early development of the iconography of the saints reflecting their position within the broader context of the establishment of Christian healers in direct opposition to their popular pagan counterparts. In the fourteenth century the appearance of SS. Cosmas and Damian was transformed mirroring the appearance of contemporary doctors, which in turn reflected the professionalisation of medicine and the role of the saints as patrons to members of that profession. This iconographic development is considered in the context of sources such as university statutes and civic sumptuary regulations that helped to shape the environment of increasing specialization that resulted in the necessity of a distinctive costume for qualified professionals. At the same time there remained continuity in the position SS. Cosmas and Damian inhabited in the popular imagination with images of the saints continuing to be associated with their traditional role as miraculous healers. Finally the large number of images commissioned by Cosimo de’ Medici in Florence in the first half of the fifteenth century are examined. At this time the position of the saints, as intercessors for and protectors of the Medici family allowed them to appear in unfamiliar locations granting them a civic and political relevance not achieved before in the history of the cult. The clear identification of the saints with the family allowed them to act as a reminder of the family’s position in Florence and for a time the doctors were known as family patrons rather than solely as doctors and healers.