&NA;During a six‐year period, six patients were treated for invasive necrotizing infection secondary to anorectal abscess. The delay in definitive diagnosis and treatment ranged from three to 14 days. All patients had significant concomitant diseases. The number of operative procedures for each patient ranged from one to nine. Antibiotics, as well as nutritional supplementation by the parenteral or enteral route, were used on all patients. Each patient had three or more complications attributable to this infection. Hospital stay ranged from 30 to 76 days. All patients survived. Factors contributing to the development of this condition are delay in diagnosis, inadequate and inappropriate treatment, and concomitant disease. Factors associated with a satisfactory outcome are examination under general or conduction anesthesia by an experienced examiner, prompt and definitive operative therapy (including drainage and removal of all necrotic tissue), antibiotics, frequent reexamination under general anesthesia, nutritional support, and close attention to concomitant disease.