Anidulafungin is an antifungal drug belonging to the echinocandin class with a potent in vitro fungicidal activity against a wide range of Candida species, including C. glabrata and C. krusei. Anidulafungin is also active in vitro against moulds belonging to the genus Aspergillus and some dematiaceous genera. Furthermore, anidulafungin demonstrates in vitro activity against Candida spp. growing as biofilms. Resistance to anidulafungin remains very rare based on recent epidemiological data. Paradoxical or trailing effects should be considered in echinocandin susceptibility testing. The in vitro activity profile of anidulafungin makes it a useful addition to the Italian antifungal armamentarium.