We describe seven patients (three men, four women; ages 27–78) who presented with signs of intestinal ischemia requiring surgical intervention. In each case, the resected colon, small bowel, or both showed striking phlebitis and venulitis affecting veins of the bowel and mesentery and resulting in ischemic injury of the bowel. In each case, this vasculopathy was the only demonstrable cause of ischemia. Arteritis involving the bowel or the mesentery was not found in any patient, and none had clinical evidence or a history of extraintestinal vasculitis. The composition of the inflammatory infiltrate was variable; in four patients, it was predominantly lymphocytic, in two necrotizing and in one lymphocytic/granulomatous. In addition, three patients also had myointimal hyperplasia of the affected mesenteric veins. Six of seven patients recovered uneventfully after surgery, suggesting a self-limited or indolent process, and the seventh died of an unknown cause. We propose the name mesenteric inflammatory veno-occlusive disease (MIVOD) to describe this unusual and previously unrecognized cause of intestinal ischemia. Its etiology is unknown, and MIVOD may represent a precursor of the recently described idiopathic myointimal hyperplasia of mesenteric veins.