Myonecrosis due to Aeromonas spp is exceptional. We report the case of a diabetic patient with liver cirrhosis who developed a rapidly progressive myonecrosis by Aeromonas veronii biotype sobria. The portal of entry was an injury after falling down in an irrigation canal. The outcome was not favourable and surgical amputation of left leg was performed in spite of antibiotic treatment with cefotaxime and tobramicin. Aeromonas spp can be very aggressive and this microorganism should be considered in the differential diagnosis of skin and soft tissue infections with myonecrosis, specially after posttraumatic wound infections with a history of freshwater exposure.