OBJECTIVES: To introduce a unique system of alias assignment for patients whose identity is initially unknown at time of admission to the emergency unit; to prevent confusion and cases of mistaken identity. METHODS: At the triage area the "unknown" patient is given a "forename" using the phonetic alphabet according to the stage of the current name cycle. The sex of the patient is included as well as the unknown status and a "surname" is added as the numerical date. Thus an unknown male patient admitted on the 24th of April at the start of a new name cycle would be known as "unknown male Alpha 24/4". RESULTS: Ten thousand alias assignments have been issued to patients since the introduction of the system in 1985. CONCLUSION: This system is a simple yet effective, tried and tested method for the unique identification of unknown patients, which allows easy communication and retrieval of data for inquiries.