Diphtheria is a highly contagious bacterial infection caused by Corynebacterium diphteriae. The aim of the study was to confirm or refute by biological examination the suspected cases of a diphtheria epidemic in the health district of Mopti. Corynebacterium diphteriae was tested by microscopy, culture and qPCR in nasopharyngeal swabs from 15 suspected diphtheria cases. Microscopy was performed by direct examination for immobility which is specific to Corynebacterium diphteriae. Gram staining was performed for the search of rather long and thin Gram-positive bacilli, irregularly shaped, rather stocky with a bulging club tip and palisade or Chinese letter shapes.The culture was performed on fresh blood agar (COS), cooked blood agar + polyvitex, M.H agar, fresh blood agar + NAC and incubated in an aerobic atmosphere enriched with 5% CO2 for 48 hours at 37°C.