Background: The transfer of information in the physician-patient relationship is important, especially in chronic diseases such as Rheumatoid Arthritis (P,4),. since it influences the perception and behavior that the patient has about his or her illness. Aim: To evaluate the level of knowledge and concern of their illness and treatment and their relationship with functional disability perception of the pain and global assessment of disease activity, in patients with RA. Patients and Methods. Cross sectional study of 104 patient, (mean age 56 years. 100 women) with RA. Demographic and clinical variables were registered. The knowledge about their illness and requirement of further information and concern about aspects of the illness and treatment. were assessed. Physical functioning was measured using the Health Assessment Questionnaire (HAQ). A visual analogue (VAS) and Likert scales were used for a global assessment of disease activity. Results., Sixty percent of patients bad only primary school studies. The median evolution of the illness was 14 years. Ninety eight percent knew their diagnosis and 91% required further information. There was a high degree of concern about the disease and treatment. The average HAQ score was 0.9. There was a statistically significant relationship between HAQ score and pain VAS (r=0.41, p < 0.01). There was a moderate agreement between the global assessment Of disease activity made by patients and physicians (Kappa=0.499; p=0.000). Conclusions: Even though patients with RA are informed about their disease, they require further information. Their highest concern is about the functional consequences of RA and they perceive a higher activity of the disease than their treating physicians (Rev Med Chile 2006; 134: 1500-06).