To investigate the distribution of patient-reported outcomes (PROs) in axial spondyloarthritis (axSpA) patients initiating a tumor necrosis factor inhibitor (TNFi), to assess the proportion reaching PRO "remission" across registries and treatment series, and to compare patients registered to fulfill the New York criteria for ankylosing spondylitis (AS) versus non-radiographic axSpA (nr-axSpA) patients.Fifteen European registries contributed PRO scores for pain, fatigue, patient global, Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), Bath Ankylosing Spondylitis Functional Index (BASFI) and Health Assessment Questionnaire (HAQ) from 19,498 axSpA patients. Changes in PROs and PRO "remission" rates (definitions: ≤20 mm for pain, fatigue, patient global, BASDAI and BASFI; ≤0.5 for HAQ) were calculated at 6, 12 and 24 months of treatment.Heterogeneity in baseline characteristics and outcomes between registries were observed. In pooled data, six months after start of a 1st TNFi, pain score was reduced by approximately 60% (median at baseline/6/12/24 months: 65/25/20/20 mm) in patients on treatment. Similar patterns were observed for fatigue (68/32/30/25), patient global (66/29/21/20), BASDAI (58/26/21/19), BASFI (46/20/16/16) and HAQ (0.8/0.4/0.2/0.2). Patients with AS, n=3281 had a slightly better response than nr-axSpA patients, n=993. LUNDEX-adjusted "remission" rates at 6 months for pain/fatigue/patient global/BASDAI/BASFI/HAQ were 39%/30%/38%/34%/35%/48% for the AS cohort and 30%/21%/26%/24%/33%/47% for the non-radiographic axSpA cohort. Better PRO responses were seen with a 1st TNFi compared to 2nd and 3rd TNFi.AxSpA patients starting a TNFi achieved high PRO "remission" rates, most pronounced in those fulfilling the modified New York criteria and for the first TNFi.