Necrotizing fasciitis is a potentially fatal infection. This disease is rarely combined with colon carcinorma. We present a 77-year-old woman who visited our ER with a chief complaint of severe abdominal pain for 3 days. Physical examination found erythematous skin with palpable crepitus and rebounding tenderness over the abdominal wall and necrotizing fasciitis of the abdominal wall was suggested. Perforated colon carcinoma with invasion to rectus abdominis resulting in abdominal necrotizing fasciitis was proved during laparotomy. When an elderly patient complains of abdominal pain, the rare situation of perforated colon carcinoma with necrotizing fasciitis should be considered.