Background: Clostridioides difficile is a sporulating anaerobe and a major entero-pathogen of both humans and animals. It produces toxins and is responsible for post-antibiotic diarrhoea and colitis that are difficult to treat and can be recurrent. In animals, the importance of C. difficile is not well evaluated. In cases of diarrhoea, its presence is not necessarily tested for. Moreover, diagnosis of C. difficile infection is difficult, because toxinogenic strains can be asymptomatically carried, if they do not produce toxins. They nevertheless remain able, after spread and transmission, to cause new, and notably community-acquired, infections. Objectives: The project aimed to i) build up and characterise a collection of C. difficile strains isolated from necropsied equidae, and ii) evaluate the frequency of C. difficile carriers in this whole equine population, together with its prevalence as a cause of infectious disease. Study design: Post-mortem survey Methods: The presence of C. difficile was systematically monitored in equideae that had been necropsied at Anses since 2019, whatever the cause of their death. Animal data (individual, clinical, epidemiological, cause of death) were registered and intestinal contents sampled to search for C. difficile. C. difficile strains were isolated and stored, forming the CloDifEqui collection. They were characterised by molecular genotyping and phenotyping. The intestinal contents of equideae displaying a toxinogenic strain were analysed for the presence of the toxins, in order to establish a diagnosis of infection. Results: Twenty strains were isolated in 80 necropsies. Conclusions: C difficile is prevalent in equine intestinal contents. Further work on molecular epidemiology and to compare these findings with the animal data is needed.