The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI), and Bath Ankylosing Spondylitis Global Score (BAS-G) have been recommended for evaluating function and disability in patients with ankylosing spondylitis (AS). The aim of this study was to develop a Chinese version of the BASDAI, BASFI, and BAS-G and assess their reliability and validity. The Chinese version was obtained after a translation and back-translation process. A total of 447 patients with adult and juvenile AS were assessed using these three instruments. Reliability was tested by internal consistency and test-retest reliability. Internal consistency of the instrument was given as Cronbach's alpha. Test-retest reliability was assessed by intraclass correlation coefficient. To assess the sensitivity to change, 153 patients were included in an 8-week follow-up study. In our analysis, the reliability of these three instruments-the BASDAI, BASFI, and BAS-G-for a 24-h test-retest showed acceptable intraclass correlation coefficients (0.92-0.94). Our Chinese versions of the BASDAI, BASFI, and BAS-G also showed 0.87, 0.94, and 0.90, respectively, with Cronbach's alpha coefficient, indicating good reliability. For sensitivity to change in 8-week follow-up, all three instruments showed 5.0 to 5.4% changes. Our Chinese versions of the BASDAI, BASFI, and BAS-G showed adequate reliability, validity, and responsiveness to clinical change. Thus, disease activity and functional status in Chinese-speaking patients with AS may be adequately evaluated with these versions of the original instruments.