Clostridium difficile associated diseases (CDADs) or C. difficile infections (CDIs) are increasing in incidence, severity and mortality. Among patients with CDIs, those with recurrent disease are less responsive to traditional therapies with commonly used drugs, such as metronidazole and vancomycin. Faecal microbiota transplantation is an old therapeutic procedure that has been recently proposed as a safe and effective treatment for CDI patients non-responsive to antibiotic therapy. In this paper we discuss the microbiological procedures that should be performed on faecal microbiota donors.