OBJECTIVES: This study aims to describe the health related quality of life (HRQOL) of the portuguese population and investigates sociodemographic differences. METHODS: Subjects randomly selected from the portuguese active population (n=2459) were assessed using the SF-36, a generic measure of HRQOL, which was converted into the preference-based SF-6D, following the Brazier algorithm. Although the sample was randomly selected, it differed slightly from the whole population. In order to correct this, post-stratified statiscal techniques were used to weight the initial results by gender and age, according to the population values. RESULTS: Mean global utility SF-6D scores were 0.70, and ranged from 0.73 (18-24 years) to 0.63 (55-64 years). The mean utility scores were 0.17 lower in the lower educational level than in the higher educational level (p<0.000). Women, people living in rural areas and the elderly reported lower levels of utility scores. Nonparametric tests showed that health utility values were significantly related to employment (p<0.000): the unskilled manual workers (0.68) reported lower utility values than the non-manual workers (0.74). For different diseases mean utility scores ranged from 0.66 (hepatitis) to 0.56 (stroke). This study was able to achieve normative data by age and gender for the SF-6D. Using QALYs as outcome measures, the difference between unskilled manual workers and non-manual workers would be equivalent to a difference of 4902€ in annual income. In this line of thinking, the difference between lower educational level and higher educational level would be equivalent to a difference of 13,889€ in annual income. CONCLUSION: We conclude that the SF-6D is an efficient tool for measuring the HRQOL in the community, so that different population groups can be compared. The preference-based utility measure used seems to adequately discriminate across different sociodemographic differences, showing that the HRQOL varies greatly between sociodemographic groups.