Stercoral perforation of the colon is rare. It is believe that the disease tends to occuer in aged patients with constipation tendency, long-term bedridden patients, or patients taken psychotropic drugs. But we have experienced two healthy patients with stercoral perforation of the colon. Patient 1, a 69-year-old man, was admitted to the hospital because of abdominal pain. Plain X-rays film and abdominal CT scan showed free air below the diaphragm and a fecal mass. Panperitonitis due to perforation of the colon was suspected, and an emergency operation was performed. The perforation of the sigmoid colon and feces in the peritoneal cavity were found. Paient 2, a 56-year-old woman, was admitted to the hospital because of abdominal pain. Abdominal CT scan revealed multiple air bubbles in the peritoneal cavity. We carried out an emergency operation, and found a perforation of the sigmoid colon with a hard fecal mass. In both cases, resection of the sigmoid colon with proximal colostomy was performed, a diagnosis of stercoral perforation of the sigmoid colon was established.