Mental health disorders are a rapidly growing public health problem. Despite the fact that lack of trust in the health-care system is considered to be an important determinant of health, there is scarcity of empirical evidence demonstrating its associations with health outcomes. This is the first study which aims to evaluate the association between trust in the health-care system and psychological distress. Cross-sectional study. The association between trust in the health-care system and psychological distress was analysed with multiple logistic regression analysis adjusting for other factors. A randomly selected representative sample of women and men aged 16-84 years from the Swedish population who responded to the 2006 Swedish National Survey of Public Health. A total of 26 305 men and 30 584 women participated in the study. None. The main outcome measure was psychological distress measured by the General Health Questionnaire. Very low trust in health-care services was associated with an increased risk for psychological distress among men (odds ratio = 1.59, 95% confidence intervals 1.25-2.02) and among women (odds ratio = 1.83, 95% confidence intervals 1.47-2.27) after controlling for age, country of birth, socioeconomic circumstances, long-term illness and interpersonal trust. Our results suggest that health-care system mistrust is associated with an increased likelihood of psychological distress. Although causal relationships cannot be established, patient mistrust of health-care providers may have detrimental implications on health. Public health policies should include strategies aimed at increasing access to health-care services, where trust plays a substantial role.