As there are few studies about evaluation of attitudes of health care workers to people with mental disorders in Brazil, a cross-sectional study was carried out to assess the health professionals' attitudes working in a university hospital in Rio de Janeiro and also examine the proportion of negative and positive attitudes endorsed by healthcare professionals in Brazil towards people with mental illness in comparison with other parts of the world. Data were collected using the Community Attitudes towards the Mentally Ill (CAMI) in a random sampling frame of health professionals (n = 246) working in a University Hospital in Rio de Janeiro between April 2013 and June 2013. The CAMI consists of four sub-scales: Authoritarianism, Benevolence, Social Restrictiveness and Community Mental Health Ideology. The results showed attitudes that range from neutral to positive, with the Benevolence and Social Restrictiveness sub-scales showing the least stigmatizing results. The following individual characteristics were associated with negative attitudes: lower levels of education and less clinical experience. In general, health workers attitudes towards service users are characterized as positive when compared with other international studies. However, educational programs for health workers should be reinforced to further promote pre-existing positive attitudes towards people with mental health and the implementation of Brazilian Mental Health Policies.