The purposes of the study are to evaluate the characteristics of gangrenous colitis and to identify clinicobiological factors. We performed a retrospective study of 75 patients in whom the diagnosis was made endoscopically and confirmed pathologically, between March 2004 and March 2010 at a tertiary teaching hospital. We classified ischemic colitis into the reversible and irreversible types (gangrenous colitis). The influence of factors, such as medical history, symptoms, physical examination, laboratory abnormalities, endoscopic findings, abnormalities on computed tomography, perioperative issues, complications, and several scoring systems, on gangrenous ischemic changes and mortality was evaluated by univariate and multivariate analyses. Ischemic colitis was classified as gangrenous ischemic type in 19 patients. The sigmoid colon was the most common site of involvement. However, the disease distribution was significantly different between the two groups. Pancolitis was most commonly observed for fulminant gangrenous colitis. A difference between the two groups was detected for several factors: age, mortality, physiologic score, APACHE II, mean arterial pressure at the time of admission, heart rate, albumin level, and sodium bicarbonate concentration. Multivariate analysis indicated four factors predictive of gangrenous colitis: absence of hematochezia, abdominal tenderness, absence of diarrhea, and albumin level. Another multivariate analysis excluding gangrenous change factors for mortality indicated four factors: arterial pH, serum sodium bicarbonate (metabolic acidosis), albumin (<3.0), and arterial oxygenation. Absence of diarrhea and hematochezia, presence of abdominal tenderness, and hypoalbuminemia could be the predictors for development of gangrenous changes of ischemic colitis.