Necrotizing fasciitis (NF) is a soft tissue infection affecting subcutaneous tissue and the muscular fascia without involvement of the muscle and can be either monomicrobial or polymicrobial. Monomicrobial infections are usually caused by group A streptococci, while infections caused by anaerobic germs usually affect immunodepressed patients. We report a rare case of NF caused by two anaerobic bacteria in an immunocompetent patient.