To evaluate the influence of TNF-α inhibitor on lipid profile and atherogenic index of plasma (AIP) in axial spondyloarthritis (axSpA) patients with long-term use of stable dose TNF-α inhibitor. AxSpA patients were enrolled in the Catholic Axial Spondyloarthritis COhort (CASCO). We collected their data annually and analyzed their lipid profile and AIP. Comparison was conducted between TNF-α inhibitor user group and non-user group. Additionally, lipid profile and AIP of TNF-α inhibitor user group were compared over 2 years. A total of 238 axSpA patients were enrolled for the present study, including 132 TNF-α inhibitor users and 106 non-users. Changes of total cholesterol (TC), TG, low-density lipoprotein cholesterol (LDL-C), and HDL-C over 2 years did not show significant difference between TNF-α inhibitor user group and non-user group. When baseline data and 2-year follow-up data were compared within the TNF-α inhibitor user group, there was no significant increase in TG, LDL-C, HDL-C, or AIP. Only TC level was slightly increased in the 2-year follow-up data for the TNF-α inhibitor user group (177.86 ± 28.73 vs. 183.08 ± 29.82, P = 0.019). Long-term use of stable dose TNF-α inhibitor did not increase atherogenic lipid profile or AIP compared to the control group. Furthermore, atherogenic lipid profile or AIP was not increased significantly in the TNF-α inhibitor user group over the 2-year follow-up. Therefore, using TNF-α inhibitor for a long term might not affect atherosclerosis of axSpA.Key Points• Managing risk factors of cardiovascular disease (CVD) such as dyslipidemia in axSpA is important because axSpA patients have increased risk of CVD.• Using TNF-α inhibitor for 2 years with stable dose did not deteriorate atherogenic lipid profile or AIP as predictor of atherosclerosis.• Maintaining stable dose of TNF-α inhibitor for long-term in axSpA may be relatively safe for managing atherogenic lipid.