The study investigated explicit and implicit attitudes towards people with mental illness among medical students (non-professionals) with no previous contact with mentally ill patients and psychiatrists and psychotherapists (professionals) who had at least 2 years of professional contact with mentally ill patients. Explicit attitudes where assessed by self-report. Implicit attitudes were measured with the Go/No-Go Association Task, a variant of the Implicit Association Test that does not require the use of a comparison category. Compared to non-professionals, mental health professionals reported significantly higher approach emotions than non-professionals towards people with mental illness, showed a lesser tendency to discriminate against them, and held less restrictive attitudes. Both groups reported negative implicit attitudes towards mentally ill. Results suggest that both non-professionals and professionals display ambivalent attitudes towards people with mental illness and that professional, long-term contact with people with mental illness does not necessarily modify negative implicit attitudes.