In recent years there has been an increasing interest in measuring health-related quality of life (HRQoL) with instruments such as the SF-36. OBJECTIVES: The aim of this study is to examine the relationship between SF 36 and socio demographic factors in a general population sample. We especially focus on differences between men and women. METHODS: Data was based on a postal questionnaire sent to a random sample of 8000 inhabitants (response rate 68%) in Uppsala County, Sweden, in 1995. RESULTS: Women reported lower scores than men on all eight dimensions of SF-36. Physical health was lower among the older for both men and women. Mental health was approximately constant with age for men and slightly higher among older women. Both physical and mental health were higher among those with higher education, income and social group. When controlling for the other variables education was not related to physical and mental health and social group was only related to physical health. The association of higher mental health scores for those with higher income was stronger for men than for women. Unemployment was associated with lower mental health, but was not related to physical health after controlling for the other variables. The association of unemployment with mental health was larger for men than for women. Physical health did not vary with marital status, but for mental health the scores were lower for persons that are single, divorced or widows compared to married persons. CONCLUSIONS: Our results indicate that inequalities in HRQoL are present with respect to several socioeconomic variables.