Necrotizing fasciitis is a rapidly progressive and potentially fatal infection. It is characterized by extensive subcutaneous and muscle necrosis. Aeromonus hydrophilia is a gram-negative faculatively anaerobic bacillus that is part of the normal flora of nonfecal sewage and is found in most water systems, soil, and fresh brackish water. Necrotizing fasciitis caused by A. hydrophilia have occurred in children who had underlying systemic diseases or immune dysfunction. We report a 14-year-old boy without underlying systemic diseases or immunodeficiency who developed necrotizing fasciitis secondary to A. hydrophilia and he was successfully treated with extensive surgical debridement and systemic antibiotics.