Abstract: A Health-Watch that provides nearly instant access to critical medical data. It is worn on the wrist like a conventional wrist watch and contains two levels of data. The first level, which contains the most critical medical data, can be displayed on the watch's alphanumeric display screen. The second level of data, which is of lower priority and is frequently more detailed, can be accessed by an external data terminal via a serial data port on the Health-Watch. The Health-Watch combines all circuitry including memory onto a single Application Specific Integrated Circuit. An UPDATE mode provides for updating medical data.