OBJECTIVES This study aims to provide estimates of EQ-5D as a function of Health Assessment Questionnaire – Disability Index (HAQ-DI) scores in patients with rheumatoid arthritis (RA) in Taiwan. METHODS Face-to-face patient interviews on a total of 140 patients aged between 30 and 70 years old were recruited at the rheumatology outpatient clinics of four hospitals located in northern, central and southern Taiwan during June 2013-May 2014. The severity distribution of patients was mild RA (Disease Activity Score [DAS 28] <3.2)(N=57), moderate RA (3.2�…DAS<5.1)(N=44), and severe RA (DAS³a5.1)(N=39). Socio-demographic and clinical information were collected, and the HAQ-DI and the EQ-5D questionnaires were completed. Generalized linear regression models were used to predict EQ-5D utility values as functions of HAQ-DI scores, age, and gender. RESULTS Patient mean age was 50.8 years old (standard deviation [SD], 11.3 years); 81.4% of the patients were women and mean disease duration was 9.65 years (SD, 6.84 years). HAQ-DI <0.5, 58%; 0.5�…HAQ-DI<1.1, 16%; 1.1�…HAQ-DI<1.6, 9%, 1.6�…  HAQ-DI<2.1, 12%; and HAQ-DI³a2.1, 4%. HAQ-DI and EQ-5D mean scores were 12.01 (SD, 7.8) and 0.67 (SD, 0.34), respectively. The models were able to predict actual EQ-5D across the range of the HAQ DI. Age and gender were found to be significant determinants in estimating the utility functions. CONCLUSIONS Utility values have very often not been assessed in the data collection process in a clinical trial. This study showed that HAQ-DI scores can be used to derive EQ-5D utility values for patients with RA in Taiwan to facilitate conducting a cost-utility analysis.