Background: Approximately one-third of people suffering from multiple sclerosis (MS) need long-term care by their families, however, we know little of their experiences. Exploring these experiences can be a guideline to improve the quality of care for MS patients. The goal of this study is to explore informal caregivers' experiences regarding care of MS patients. Materials and Methods: A qualitative content analysis method was used to conduct this study in 2014. The study participants were 23 informal caregivers of MS patients who were chosen by purposeful sampling from the MS association of Iran. Data was analyzed by content analysis. Results: The analysis resulted in the emergence of six themes and seventeen subthemes. The main themes were being plagued, mental health damage, being captive among obstacles, perception of the affected family, being an emotional supporter, and need to maintain the functional independence of the patient. Conclusions: The findings represent the mean of long-term care by informal caregivers of MS patients, as well as the needs and challenges of this relationship. The findings can serve to create a framework for developing nursing care processes and planning educational sessions and support programs for MS patients and their informal caregivers.