Background: People with mental illness and substance abuse are in great need of care and treatment. To increase the chances of recovery, both diagnoses need to be identified. Mental illness and substance abuse are perceived as deviant in society and among caregivers, with the result that the person is not seeking care and likely to deteriorate in their health. The nurse is obliged to use his/hers understanding in a fair and unprejudiced way, and deal with the person with respect and understanding regardless of the disease. For nurses in the municipal health care responsibilities for people with comorbidity leads to a higher workload and stress. Previous research shows that nurses lack skills in psychiatric nursing, causing uncertainty in health care meeting. Aim: The purpose of the study is to describe nurses' experiences of people with mental illness and substance abuse in municipal health care.Method: A qualitative method with individual interviews were used. The sample consisted of seven nurses, three psychiatric nurses, a district nurse and three general nurses. Participants were six women and one man, between twenty-five and fifty-two years old. The collected material was analyzed by qualitative content analysis. Result: Three categories are presented in the outcome - Patient needs that are difficult to master, Conditions for a good care relationship and Organizational shortcomings create role confusion. These categories created a theme: Comorbidity - multifaceted and difficult to master. Conclusion: We need greater knowledge of psychiatry in the municipal health service. For this to happen, we need understanding from the top of the organization regarding the illuminated phenomenon and understanding of psychiatric nurses' skills. Further research on how the organization can be improved could contribute to greater understanding and thereby improve patient situation.