Five extremely low birth weight (ELBW) infants were treated in our institution for the milk curd syndrome, a milk bolus intestinal obstruction. The medical records of the five patients, who all underwent surgery, were retrospectively reviewed. History and examination are usually sufficient to diagnose the milk curd syndrome in ELBW infants. Confirmation with an abdominal X-ray may be possible but the X-ray findings may be mistaken for localised necrotising enterocolitis (NEC). Contrast enemas in an attempt to shift the bolus obstruction may be dangerous, and have a low success rate. Enterotomy and removal of the bolus is a safe and effective treatment if the diagnosis is early, otherwise resection with or without diverting ileostomy may be necessary. It appears that after years of disappearance, the milk curd syndrome has again become a clinical entity. It is probably due to a combination of high calcium and fat intake in an ever increasing population of ELBW infants.