Background: There are few studies that describe differences in measures of burden and participation in care relating to whether the relatives live with or apart from the person with a mental illness. Aim: To investigate different aspects of family burden, need for support and participation in care situations specifically considering whether the relative and the patient are living together or apart. Method: 162 relatives (73 relatives of committed patients and 89 relatives of voluntarily admitted patients) answered a semi-structured questionnaire concerning their situation as a relative of a severely mentally ill person. Results: There was increased experienced family burden in several aspects due to the relative and patient living together. However, relatives who lived with the patient were less likely to believe that the patient would be better off dead, experienced more participation in the patient’s treatment and more often viewed the psychiatric services as being of good quality than those relatives who did not live with the patient. Conclusion: Persons with a severe mental illness who are admitted to inpatient units are in need of different aspects of intensive psychiatric care. Some of these needs are supplied by relatives in everyday life, often without any support. In providing for the needs of relatives, in relieving their burden, the psychiatric services needs to implement different methods according to whether the relatives live with or apart from the patient.