Necrotizing enterocolitis (NEC) in preterm neonates is associated with symptoms of ileus occurring within the first days to weeks of live. The present case describes a mature colt with intermittent colic 20 hours post partum. Prominent clinical findings included a rectal temperature of 36.9°C, hyperperistalsis and mild abdominal distension. Immunoglobulin concentration and plasma protein concentration were decreased with < 400 mg/dl and 50 g/l, respectively. Radiology of the abdomen revealed moderate meteorism and multiple air-fluid levels. Following initial conservative therapy a laparotomy was performed. Moderate tympania and severe thickening of the intestinal wall with a grey and blue discoloration of the ascending colon were present. Because of progressive disease the colt was euthanised one day after surgery. Histology showed a severe, acute, transmural, catarrhal colitis with fibrinoid angiodegeneration and necrosis of the submucosa. Clinical, surgical and histologic findings are consistent with necrotizing colitis. The etiology of NEC is unknown, however, a multifactorial pathogenesis is discussed.