Four children, three girls in the age range up to 14 months and a boy aged 10 years, were admitted because of button battery ingestion. In two patients, the course was uncomplicated, with spontaneous passage of the batteries. Two other patients, a girl aged 11 months and a girl aged 6 weeks, developed severe complications: stenosis of the oesophagus in one patient and a dramatic clinical course with a tracheo-oesophageal fistula and oesophageal damage in the other. Ingestion of foreign bodies in children is a common problem. With the increased use of miniature electronic devices, the incidence of button battery ingestion is rising. Ingestion of a battery is an indication for urgent referral and radiological examination. Electrochemical tissue damage and impaction may lead to serious complications within hours. If the battery is located in the oesophagus, endoscopic removal should be attempted as soon as possible. A conservative approach can be followed when the battery is located in the stomach or beyond, and complaints are absent.