The ileosigmoid knot. The ileosigmoid knot (ISK) is a rare cause of intestinal obstruction. Unfamiliarity with the condition could have disastrous consequence at surgery. Over the past 20 years, we have encountered seven cases. Analyzing the data gathered from these, and on reviewing the literature, we found it possible to arrive at a preoperative diagnosis in two patients. Four patients were women, two of whom developed the obstruction in the postpartum period. One of the males was found to have an inflamed Meckel's diverticulum included in the knotting. The symptoms and the clinical findings were nonspecific. The characteristic x-ray findings of a double closed loop obstruction, was seen in only three patients. Resection of gangrenous bowel with anastomoses was feasible in four. Unlike in other series, primary anastomosis of the large gut was undertaken. There were two deaths early in the series. Guidelines to the management have been suggested. 