In 2003 the Board of the Italian Society of Occupational Medicine and Industrial Hygiene (SIMLII) decided to adopt a graphic symbol of the Society, that would be easy recognizable and could be used for the 75th anniversary of its foundation, in 1929. The task of drawing up proposals for the symbol was entrusted to the Section of Occupational Medicine and Toxicology of the University of Perugia. The article explains the difficulties in adequately representing the various different types of information enclosed in the logo; in particular, in choosing the most appropriate way to represent the art of medicine between Mercury's caduceus and Aesculapius' symbol. The logo chosen by the Board of the Society on 11 November, 2003, is illustrated by its author, Professor Umberto Raponi. The symbol officially came into use for the 67th National Congress of SIMLII, held in Sorrento, 3-6 November, 2004.