Purpose: The aims were to translate the Evaluation of Daily Activity Questionnaire (EDAQ) into Turkish, then test validity and reliability in people with rheumatoid arthritis (RA) in Turkey. Material and Methods: Phase 1: The EDAQ was forward and backward translated, culturally adapted following cognitive debriefing interviews with participants with RA (n = 10) and finalized by an expert committee. Phase 2: Participants (n = 215) completed a questionnaire including the EDAQ, Health Assessment Questionnaire (HAQ), and Short-Form 36 v1 (SF-36v1). Two weeks later, the EDAQ was again completed for test–retest reliability (n = 82:38%). Internal construct validity was assessed using Rasch analysis. Internal consistency, concurrent validity, and test–retest reliability were assessed. Results: Following cultural adaptation, one item was removed, and examples increased or changed. Cronbach’s α values were 0.71 − 0.93 for all EDAQ domains, that is, acceptable to good. The EDAQ met Rasch model requirements for fit (excellent construct validity: p > 0.05). Concurrent validity was moderate to strong for most EDAQ domains with HAQ (rs 0.49–0.81) and SF-36-v1 Physical Function (rs 0.42–0.70). There was excellent test–retest reliability for all domains (ICC (2,1): 0.95–1.00). Conclusion: The Turkish EDAQ is a valid, reliable measure of daily activity ability for use in practice and research with Turkish speakers with RA
