Ingested metallic foreign bodies (MFBs) are usually diagnosed by taking X-ray films of the neck, chest and/or abdomen. This study evaluates the use of a hand-held metal detector (HHMD) for the diagnosis and localisation of MFBs. In a prospective study, 53 consecutive paediatric patients with history of a swallowed MFB were examined with X-rays and HHMD. In 47 children, the MFB could be verified radiologically. Coins were most frequently swallowed. The HHMD could detect and locate all coins but only 47% of other MFBs. There were no false-positive results. A HHMD is an effective tool for screening the location of suspected ingested coins. This method is easy, inexpensive and free of radiation. Very small MFBs cannot be reliably detected. If an innocuous metallic foreign body is clearly identified with a hand-held metal detector in the stomach or lower gastrointestinal tract of an asymptomatic child, additional radiological confirmation is not required.