Background: The United Nations proclaimed 2001 the "International Year of Volunteers". Little is known about factors influencing the attitude to volunteering in psychiatry. However, knowledge about these factors is important as target groups to be addressed by an awareness and promotion campaign could be identified. Aims: To determine the influence of demographic, psychological and sociological factors on the attitude to volunteering in psychiatry. Methods: Multiple logistic regression analysis of the results of an opinion survey conducted on a representative population sample in Switzerland (n = 1737). Results: Public attitude is mostly positive. It depends, however, on the form of volunteering. Two explanatory models for volunteering in psychiatry were found: first, the "antipathetic person" having social distance to and negative stereotypes towards the mentally ill. Second, the "people with social responsibility and commitment" who have former experience in volunteering, a positive attitude to community psychiatry, interest in mass media, a social profession and perceive discrimination of mentally ill persons. Age and gender are significant predictors. Conclusions: An awareness and promotion campaign to use the vast potential of people willing to volunteer in psychiatry pan be primarily focused on those with a basic interest in social issues. Volunteering must be limited in time and responsibility. Contacting people with a positive attitude by mass media is a promising way.