Background: To assess the subclinical cardiovascular affection in juvenile idiopathic arthritis (JIA) Egyptian patient subtypes using Doppler ultrasonography (US) for carotid and femoral arteries and detecting their predictors Results: Forty percent of the patients were polyarticular type, while 40% were systemic onset and 20% were oligoarticular. There was a statistically significant difference between JIA and controls in all parameters of subclinical atherosclerosis by ultrasonography except right external carotid velocity and (right and left) femoral velocity. There was also a highly significant increase in intima-media thickness (IMT) in systemic onset type of JIA. There was a statistically positive correlation between increased internal carotid velocity (right and left) and high erythrocyte sedimentation rate (ESR), high-sensitivity C-reactive protein (hs-CRP), lipid profile, and disease activity. High disease activity and lipid profile were valid predictors of subclinical atherosclerotic cardiovascular affection in JIA. Conclusion: Increased cardiovascular risks and subclinical atherosclerosis in patients with JIA especially systemic onset type may be due to higher prevalence of multiple risk factors in these patients. Doppler ultrasonography is a simple, non-invasive technique which can be used to detect subclinical atherosclerosis in JIA. Control of disease activity by treat to target strategy and proper diet control should be applied for every patient with JIA especially those with systemic onset type for future prevention of cardiovascular disease.