We report a case of Fournier's syndrome caused by a perianal abscess which developed a widespread preperitoneal absces extending from the pelvic cavity to left side of the umbilicus, with a review of the literature. A 55-year-old man was admitted to the hospital because of a perianal pain and difficulty of urination. After an incisional drainage for the perianal abscess, his condition and laboratory data seemed to improve. But inflmmatory changes grew worse again and redness, swelling and tenderness appeared in the lower abdominal wall. Computed tomography (CT) revealed a widespread abscess in the preperitoneal space. A wide drainage and irrigation made a remission and he was discharged from the hospital 31 days after the 2nd operation. It is very important to entertain a possible existence of this disease, which can spread rapidly and sometimes become fatal, when we encounter the patients with severe infection of the anorectal and urogenital region, especially whose condition and abnormal laboratory data prolong or deteriorate.