Background: Many people with mental health problems do not seek professional help but their use of other sources of help is unclear. Aims: To investigate patterns of lay and professional help-seeking in men and women aged 16-64 years in relation to severity of symptoms and sociodemographic variables. Method: Postal questionnaire survey, including the 12-item General Health Questionnaire (GHQ-12), sent to a stratified random sample (n=15222) of the population of Somerset. Results: The response rate was 76%. Only 28% of people with extremely high GHQ-12 scores (≥8) had sought help from their general practitioner but most (78%) had sought some form of help. Males, young people and people living in affluent areas were the least likely to seek help. Conclusions: Health promotion interventions to encourage appropriate help-seeking behaviour in young people, particularly in men, may lead to improvements in the mental health of this group of the population.