To systematically investigate the scope and nature of discrimination and positive treatment experienced by adults with mental health problems when using health services in an Australian population-based survey.Australian adults (n = 1381) who reported a mental health problem or scored high on a screening questionnaire were interviewed about their experience of discrimination and positive treatment from healthcare professionals. Descriptions of experiences were content-analysed to identify key characteristics.In all, 11.8% of respondents reported discrimination from a health professional in the past 12 months. The most common types of discrimination included being treated dismissively, being judged and not being listened to, particularly regarding personal history and treatment needs. In contrast, 40.4% reported being treated more positively by their health professional because of their mental health problem. Key types of positive treatment by health professionals were being supportive and understanding and being a good listener. Good quality care approaches were also appreciated, including making a referral, being engaged in the treatment process, regularly checking the status of the person's mental health and providing information.A minority of respondents with mental health problems had experienced discrimination from their healthcare professional, potentially interfering with recovery. Anti-stigma education interventions for healthcare professionals should address how to increase knowledge and understanding of mental health problems, reduce negative attitudes and encourage supportive behaviours.