Background: Juvenile Idiopathic Arthritis (JIA) is a heterogeneous group of chronic inflammatory joint disorders that primarily affect children and adolescents. Aim: To evaluate the levels of anti-carbamylated protein (anti-CarP) antibodies in Juvenile Idiopathic Arthritis patients and to determine their association with serological parameters and disease activity. Methods: This Case control study was carried out at pediatric rheumatology unit, Children’s Hospital Zagazig University and Elahrar Teaching Hospital in Zagazig on 48 children with Juvenile Idiopathic Arthritis who were admitted to Rheumatology Pediatric Unit and 48 healthy children age and sex matching as a control group. Results: There was a statistically significant positive correlation between anti-carbamylated antibodies and each of CRP [r=0.25, P=0.04], JADAS-10 CRP [r=0.028, P=0.007], CHAQ [r=0.53, P<0.001], JSNS [r=0.79, P<0.001]. The analysis revealed that anti-carbamylated antibodies was a valuable diagnostic marker for JIA with AUC of 0.82. At [12.3] cut off point, anti-carbamylated antibodies had sensitivity of 54.17%, specificity of 100%, PPV of 100% and NPV of 68.57%. there was statistically significant differences among JIA subtypes in anti-carbamylated antibodies as it was higher among poly-articular RF positive group [100%] in comparison to in oligo-articular group [53.3%] and in poly-articular RF negative group [42.9], [p=0.01]. Conclusion: Anti-carbamylated protein (anti-CarP) antibodies can be used as a biomarker for the diagnosis of Juvenile Idiopathic Arthritis (JIA) by measuring differences between their levels in JIA patients and those in the healthy controls, as well as can Anti-carbamylated protein (anti-Carp) antibodies be used in predicting JIA development, disease activity, and joint destruction.