The purpose of this article is to describe the content and the development of the model to promote self-determination of patients with rheumatoid arthritis from a point of view of patients and nurses. For the patients the data were gathered using semistructured interviews and for the nurses through three focus groups in the initial and evaluation phases. The data were analysed by themes using qualitative content analysis. The model consisted of the concept of self-determination, impediments to and preconditions for self-determination, promoting and focusing on consequences. Patient's activity was a new view of the concept. Impediments to self-determination were linked to limitations and preconditions to patients' freedom to express themselves. Support developed an important factor promoting self-determination. The results indicate a clear need for various types of supportive nursing care to promote self-participation in patient care.