The functional capacity of 46 patients with rheumatoid arthritis was assessed by means of two systems of investigation. Three different questionnaires were used. One set of each was filled out by the patient himself; the other with the help of the occupational therapist. The results obtained were tested for their reliability. In addition they were also compared to the Ritchie-Index (method of simple measurement of disease activity) of thirty patients. The disability of each patient could be assessed with sufficient precision. A correlation to the Ritchie-Index was also registered.