OBJECTIVE: The pathogenesis of axial spondyloarthropathy (axSpA) is unclear. It is highly associated with HLA-B27 and other genes. In recent years, anti-CLIP-ABS has been identified in patients with axial spondyloarthropathy. our aim was to detect the positive rate of anti-CLIP-ABS in axSpA patients and the sensitivity and specificity of anti-CLIP-ABS for the diagnosis of axSpA compared to controls. METHODS: Anti-CD74 IgG antibodies in the sera of patients with axSpA and non-SpA were analyzed by ELISA with reagents developed by AESKU that are specific for CLIP. A cut-off point of ≥4 SD for either unit was used to differentiate the results. A blinded approach was applied to the laboratory staff. RESULTS: We analyzed 145 sera from 94 axSpA and 51 non-SpA patients. axSpA patients were predominantly male and younger. 72 patients were HLA-B27 carriers. anti-CLIP-ABS was detected in 85.1% of axSpA patients, but only 7.8% of non-SpA patients (p ≤ 0.0001). Patients with axSpA had higher levels of anti-CLIP-ABS than those with non-SpA: mean 14.5 versus 0.8 AU (P≤0.0001). The sensitivity of anti-CLIP-ABS for the diagnosis of axSpA was 85.1%, the specificity was 92.2%, and the likelihood ratio (LR) was 10.8 for LR+ and 0.08 for LR-. 87.5% of axSpA patients were positive for anti-CLIP-ABS with HLA-B27, but only 14.9% were negative for anti-CLIP-ABS, compared with 23.6% for HLA-B27. negative was 23.6%. Conclusion: anti-CLIP antibodies are associated with axSpA. The likelihood of diagnosing axSpA was higher using anti-CLIP antibodies than with HLA-B27. The study of SpA without imaging manifestations as well as peripheral SpA using this method helps to further establish its value in clinical practice.