Background: An increasing number of South Africans utilise primary healthcare services (either in the state or private sector) for mental health concerns; hence, there is a need to objectively assess these doctors’ attitudes and knowledge of mental illness.Aim: To investigate aspects of knowledge and attitudes towards mental illness of a group of private and state-employed non-specialist medical doctors.Method: Doctors in the state sector who were working at a primary healthcare level and who were not working towards, or did not hold, a specialist qualification were considered eligible for the study. Doctors in the private sector who were working as general practitioners and who did not hold a specialist qualification were considered eligible for the study. Data were collected by means of a self-administered questionnaire. A link to the study questionnaire, information about the study, details of the researcher and matters pertaining to informed consent were emailed to potential participants.Results: Of the 140 practitioners who responded to the survey, 51.4% (n = 72) worked in the state sector, 41.4% (n = 58) worked in the private sector and 7.1% (n = 10) worked in both the state and private sectors (χ21 = 45.31, p 0.010). The majority ( 50%) of participants in all three groups had a positive attitude towards mental illness (χ22 = 1.52, p = 0.468). Although there were no significant associations between attitude and socio-demographic characteristics (p 0.05), male SS doctors reported feeling less comfortable when dealing with mentally ill patients (p = 0.015); SS doctors who did not have family contact with mental illness were less likely to feel that mentally ill patients did not pose a risk to others (p = 0.007), and PS doctors under the age of 35 years were more likely to feel adequately trained to treat mental illness (p = 0.026). The majority ( 50%) of participants in all three groups had an adequate level of knowledge of mental illness (modal scores = 10). There were no significant associations between knowledge and socio-demographic characteristics (p 0.05).Conclusion: Despite the findings of a positive attitude and adequate knowledge of mental illness amongst the participants of this study, it is recommended that more targeted interventions are established to further improve mental health awareness and knowledge of doctors at both undergraduate and postgraduate levels of study.