The National Health Survey (NHS) has been used to calculate the percentage of the population with private health insurance at both the nationwide and regional levels. Schooling and occupation have been used as proxies for income level in calculating the percentage of the population with private health insurance. The impact of chronic diseases has also been analyzed in relation to the purchase of private health insurance. A comparative analysis of the NHS from 1995-1996 to 1998-1999 showed an increase of 1% and 0.7% (for males and females, respectively) in the proportion of the population with health insurance. Level of income shows a clear inf1uence on the acquisition of private health insurance. Individuals with medium and high levels of schooling, both males and females, are far more likely to have private insurance. Chronic diseases also have an impact on the purchase of private health insurance. According to regional analysis of NHS 1998-1999, the Greater Lisbon Metropolitan Area showed a higher percentage than the nation as a whole.