The renewed interest in leptospirosis derives from the expansion of this infection which, broken out from its historical strictly professional role, now interests wider categories of the population, represented by frequenters of zones with water or swamp for sport or week-ends. A greater knowledge therefore is needed on the diffusion of leptospirosis and its epidemiology which is notoriously non-homogeneous and variable. The necessity for the meeting arose from this new reality, not sufficiently known, of this infection, and from the necessity to cover the national territory with reference centres coordinated by the Istituto Superiore di Sanità and in the more general epidemiological picture promoted by the WHO.