OBJECTIVE This study investigated the clinical picture of gangrenous sigmoid volvulus presented by Indian patients to describe the various patterns of gangrene and to identify the risk factors leading to the very high mortality from this disease. METHODS A structured protocol including nine parameters was used to study risk factors in 76 patients treated at two major teaching hospitals in India. The clinical picture of patients at the two hospitals did not differ significantly. RESULTS Contrary to expectations, we found gangrene in 26% of cases extending beyond the area of constriction into the rectum/descending colon. This extension was sometimes patchy and had an ill defined line of demarcation, which may lead to an error in judgment and cause a failure of anastomosis, which can be fatal. Risk factors were age over 60 years, the presence of shock on admission and a history of previous episodes of volvulus. CONCLUSIONS This study identified three risks for survival. It is suggested that all patients with nongangrenous sigmoid volvulus undergo a recurrence-prevention procedure immediately or electively. We also found that extension of gangrene beyond the confines of the constriction is not uncommon, calling for caution on the part of the treating surgeon.