To examine the association between ethnicity and disease activity in patients with juvenile idiopathic arthritis (JIA), and to determine the association of ethnicity with disease severity and disability in this population. CARRAnet, a US database containing information (collected between May 2010 and June 2011) on almost 3,000 subjects with JIA, was used. Demographic variables were compared between Hispanic patients and non-Hispanic patients. Mann-Whitney and chi-square tests were used to compare indicators of disease activity, as well as imaging evidence of joint damage, and Childhood Health Assessment Questionnaire (CHAQ) scores between ethnicities. Two linear regression models were used to determine the association of ethnicity with number of active joints in JIA, and the association between ethnicity and disability (CHAQ scores). A total of 2,704 patients with JIA (277 Hispanic; 2,427 non-Hispanic) were included. Income and health insurance coverage were higher in non-Hispanics. RF-positive polyarticular JIA, positive RF and anti-CCP, as well as use of systemic steroids were more frequent in Hispanics. Imaging evidence of joint damage was present in 32 % of the Hispanic patients compared to 24 % of the non-Hispanic patients (p = 0.008). In multivariate linear regression analyses, the number of active joints was significantly higher in Hispanics than in non-Hispanics (p = 0.03), as well as CHAQ scores (p = 0.003), after adjusting for confounders. Hispanic patients with JIA had higher disease activity than non-Hispanic patients, as well as higher disease severity and disability. Since ethnicity influences disease activity, severity, and disability, different management and treatment plans should be planned accordingly.