Gianfranco Donelli obtained his master degree in Biological Sciences from the Sapienza University of Rome in 1966. From 1967 onwards he worked as researcher at the Istituto Superiore di Sanità (ISS - Italian National Institute of Health) in Rome in the field of molecular biology and ultrastructure of bacteriophages and human intestinal viruses. In 1975 he was appointed Director of the Electron Microscopy Unit and in 1979 he became the Research Director in molecular biology. In 1982 he founded the Laboratory of Ultrastructures of ISS that has been led by him till 1996. In those years his main research interests covered many aspects of cellular microbiology with special reference to the mechanism of action and the pathogenetic role of toxins and other bacterial virulence factors. He has been invited since 1977 to serve as visiting professor in the Universities of Ancona, Naples, Perugia, Rome and Urbino and in 1999, he was appointed full Professor of Microbiology.