Background:Few studies, especially in Iran, have assessed the status of family participation in the care of the hospitalized patients.Objectives:This study was conducted to assess why family members partake in caregiving of their patients in hospitals, the type of care that family provide, and the outcomes of the participation in the opinions of nurses and family members.Patients and Methods:In this comparative-descriptive study, data was collected by a two- version researcher-developed questionnaire, from 253 family members of patients by quota sampling method and 83 nurses by census sampling method from wards which had licensed for entering the families. Each questionnaire has three sections: the care needs of the patients which family participated to provide, the reasons to take part, and the outcomes of this collaborative care. The data was analyzed using descriptive statistics and also chi-squared test through SPSS software version 11.5.Results:The patients received more unskilled and non- professional nursing care from their family members. Most of the nurses and families believed that family participation is both voluntary and compulsory. The shortage of personnel in different categories of nursing and speeding up the patient-related affairs were the most important outcome of the participation, from the nurses’ viewpoint was speeding up the patient-related affairs and from the side of the family members, it was the patients’ feeling of satisfaction from the presence of one of their relatives beside them.Conclusions:Co understanding, skillfulness and competence of families and nurses in collaboration with each other were not good enough.Few studies, especially in Iran, have assessed the status of family participation in the care of the hospitalized patients.