OBJECTIVES: Rheumatoid arthritis and osteoarthritis are important causes of morbidity in the population. The objective of this study was to quantify the loss in health related quality of life due to RA and OA diseases. METHODS: 127 RA and 167 OA consecutive outpatients were included in the study at 9 sites in the capital and in the rest of Hungary in 1999. Both patient groups filled in the EQ-5D questionnaire. In addition, RA patients filled in the HAQ while OA patients filled in the WOMAC questionnaires. EQ-5D weighted index values of the two patient groups were compared to those of the general Hungarian population. HAQ and WOMAC scores were correlated to EQ-5D weighted index values. RESULTS: Five age groups were defined as people between the age of 35-44, 45-54, 55-64, 65-74, and 75-84. Mean EQ-5D weighted index values were 0.634, 0.517, 0.459, 0.34, and 0.34 among RA patients and 0.688, 0.429, 0.339, 0.415, and 0.359 among OA patients, respectively. Corresponding EQ-5D weighted index values are known to be 0.875, 0.813, 0.736, 0.705, and 0.675 among the general population. Differences between the general population and the patients groups were statistically significant (p<0.05). The correlation coefficient between the EQ-5D weighted index and the HAQ, WOMAC Pain, WOMAC Stiffness, WOMAC Physical function scores were –0.552, -0.552, -0.187, and –0.553, respectively. CONCLUSIONS: Rheumatoid Arthritis and Osteoarthritis diseases lead to huge losses in health related quality of life and this should be recognised in global health statistics and in health policy priority setting.