The Australian Unity Wellbeing Index has been designed as a new barometer of Australians‟ satisfaction with their lives, and life in Australia. It is based on, and develops, the theoretical model of subjective wellbeing homeostasis. The Index comprises two sub-scales of Personal and National Wellbeing. Data were collected through a nationally representative sample of 2,000 people in April/May 2001. Factor analysis confirmed the integrity of the two sub-scales and, confirming empirical expectation, the average level of life satisfaction was 75.5 percent of the scale maximum score. Group comparisons revealed that all age groups maintained their Personal Index score within the normal range. In addition, people in country areas were more satisfied with their personal lives than city-dwellers, but less satisfied about the national situation, and people who had recently experienced a strong positive event evidenced a rise in wellbeing, whereas those who had experienced a strong negative event evidenced wellbeing in the low-normal range. It is argued that these data generally support homeostatic theory. However, an unusual result was that females were more satisfied with their own lives than males. A tentative argument is advanced that this may represent a constitutional difference. It is concluded that the Australian Unity Wellbeing Index has potential as a valid, reliable and sensitive instrument to monitor national wellbeing.