The aim was to investigate the importance of aspects of health for patients with axial SpA (axSpA) and to explore differences across different subgroups.A Best Worst Scaling exercise was conducted in patients with axSpA from 20 countries (10 patients per country) worldwide. Using the 17 items of the Assessment of SpondyloArthritis international Society Health Index, a set of 17 choice tasks was generated. Patients had to indicate in each choice task the most and least important out of four varying items. The hierarchical Bayes method was used to estimate the relative importance score for each item (summing to 100). Subgroup comparisons were performed for relevant demographic (gender, age, work status, geographical area and education) and disease characteristics (SpA phenotype, disease duration and disease activity) using one-way analysis of variance or the Mann-Whitney U-test.The experiment was completed by 199 patients with axSpA [117 (58.8%) men, mean (sd) age 42.3 (13.6) years, mean (sd) disease duration 11.1 (11.2) years, 130 (65.3%) AS]. The highest relative importance was assigned to pain (14.2; 95% CI: 13.8, 14.6), sleep (10.3; 95% CI: 9.6, 11.0), being exhausted (9.6; 95% CI: 9.0, 10.3), standing (9.25; 95% CI: 8.5, 10.0) and motivation to do anything that requires physical effort (8.7; 95% CI: 8.1, 9.3). The lowest relative importance was assigned to sexual relationships, toileting, contact with people, driving and washing hair. Differences between subgroups were small or in aspects with lower importance.A clear gradient was seen in the importance of the different aspects of health that impact functioning of patients with axSpA. Differences between subgroups were small or non-existent. These findings help to align clinical care to patients' needs.? The Author 2016. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved. For Permissions, please email: firstname.lastname@example.org.