A radio frequency patient identification and information system includes a transponder which may be incorporated in a device which may be strapped to a patient's wrist or ankle, or hung around the patient's neck by a cord, carried as a card or label in the patient's purse or wallet, or embedded under the patient's skin. The transponder, in the form of an RFID tag, operates at a frequency standardized for this application, has a read/write memory of about at least two thousand bits-an amount sufficient to store information related to the patient's complete identification, such as home address, work address, next of kin, the patient's current primary care physicians, important contact telephone numbers, insurance information, complete medical history, all known allergies, and past and presently-prescribed medicines. The tag may be equipped with a transmission enable switch to prevent unauthorized access to the patient's medical history and other potentially sensitive information. An interrogator/reader/writer device is provided at each emergency health care facility and at the office of each health care provider.