AIM: To investigate in what ways clinical supervision can influence district nurses', psychiatric nurses' and mental health care workers' ethical decision-making in home care of people with mental illnesses. BACKGROUND: Nursing staff frequently have to make difficult ethical decisions when caring for mentally disturbed patients in the home. METHODS: This study is a descriptive, correlational study. Data was collected by a cross-sectional survey that focused on psychiatric nurses, district nurses and mental health care workers (n = 660). RESULTS: Health care professionals, who received supervision as support in their clinical nursing work, perceived that they felt more secure in decision-making, felt safer in their relationship with the patient and had gained a deeper insight into the meaning of security for the patient as well as for the carer. Furthermore, they regarded taking over responsibility for the patient, when necessary, as their moral right and that care and treatment in the patient's home could mean that the patient's integrity was violated. CONCLUSIONS: The results emphasize the need for clinical supervision as support for nursing staff, as it leads to their acquiring a greater sense of self-esteem. There is also a need to clarify the professional role of nurses through integration of theoretical and clinical knowledge. The importance of supervision is illustrated by means of previous studies.