Background: People with mental disorders often report unmet medicine information needs and may search for information on medicines from sources including the Internet, telephone services, books and other written materials. Objective: This study aimed to identify and describe the sources of medicines information used by people with and without mental disorders. Methods: A cross sectional postal survey was mailed to a nationally representative sample (n = 5,000) of Finns aged 15-64 years in spring 2005. Completed responses were received from 3,287 people (response rate 66 ), of whom 2,348 reported using one or more sources of medicines information during the past 12 months. Of those who reported one or more sources of medicines information, 10 (n = 228) reported being diagnosed with or treated for a mental disorder. The main outcome measures were the sources of medicines information used by people who did and did not report being diagnosed with or treated for a mental disorder. Results: Among respondents with and without a mental disorder, physicians (83 vs. 59 ), pharmacists (56 vs. 49 ) and patient information leaflets (53 vs. 43 ) were the most common sources of medicines information. After adjusting for age, gender, level of education, working status and number of chronic diseases, respondents with mental disorders were more likely to use patient information leaflets (OR 1.47, 95 CI 1.06-1.98) and the Internet (OR 1.64, 95 CI 1.02-2.64) as sources of medicines information than respondents without mental disorders. Conclusions: The results indicate that physicians and pharmacists are the most common sources of medicines information among people both with and without mental disorders. However, patient information leaflets and the Internet were more commonly used by people with mental disorders. There may be an opportunity for clinicians to better exploit these sources of medicines information when developing medicines information services for people with mental disorders.