Objective: To explore how patients and relatives experience and talk together about their life with inflammatory arthritis. Design: Qualitative research. Setting: A convenience sample was used. Participants were recruited in seven rheumatology departments in France. Participants: Patients with rheumatoid arthritis or spondyloarthritis, agreeing to participate in the study with a relative, age at least 18 years. Data collection and analysis: Two psychologists conducted face-to-face interviews with 20 patient-relative dyads (40 individuals). A thematic analysis followed a general inductive approach. Results: Saturation was reached after interviews with 20 dyads. The analysis revealed four main themes: (a) disease 'lived' together: a new role for the relative (providing help in physical tasks, emotional support, acting as a driving force, having a role in medical care) and communication around the disease (not focusing on the disease); (b) impact of the disease on the relationship; (c) social impact of the disease on the dyad (social isolation); (d) difficulties and needs of the relative (need to better know the disease). Conclusion: This study has highlighted the importance of recognizing the role of the relative in the management of inflammatory arthritis disease, especially when medical decisions are shared with professionals. A joint approach to treatment is a basis for coping with the disease. This approach supposes (a) discussions about relatives' new roles to clarify them, (b) patients' and relatives' communication skills and (c) a good understanding of each other, which can be improved by providing information on the disease and coping strategies for both the patient and the relative.