In this study, we performed urinary proteomics to explore the landscape of urinary proteins in patients with AOSD and identified three glycoproteins, α-1-acid glycoprotein 1 (LRG1), orosomucoid 1 (ORM1, alternatively named leucine-rich α-2-glycoprotein 1, AGP1), and orosomucoid 2 (ORM2 or AGP2), as potential non-invasive markers assisting the diagnosis of AOSD. Here, ORM2 is linked to adult-onset Still disease.