An autopsy case of a 4-month-old boy who died immediately after being fed by a member of the staff of a day-care centre is described in this report. An autopsy certified that the cause of death was the aspiration of milk. There was no other apparent reason for the aspiration of milk into the trachea except for the left superior cornual defect of the thyroid cartilage. We therefore conclude that it was this defect which led to the aspiration of milk into the trachea.