【Background】Coronary artery lesions (CALs) late after Kawasaki disease (KD) have been associated with endothelial dysfunction and low-grade inflammation, surrogate markers for atherosclerosis. Virtual histology-intravascular ultrasound (VH-IVUS), a new method to assess coronary plaque composition and morphology in vivo, was recently introduced. We tested the hypothesis that CALs in patients long after KD are accompanied by atheromatous plaque-like features, as assessed by VH-IVUS.【Methods】VH-IVUS was performed in 11 Japanese KD patients [age: 19y7m (mean) ± 1y4m (SE); an interval after KD: 16y11m ± 1y5m] with CALs. We investigated each segment and/or coronary artery lesion in each patient: 5 sites with a localized stenosis (LS), 14 sites with an aneurysm (AN), 24 sites with a regressed aneurysm (RA), and 39 sites with normal coronary artery (N) from the onset. After baseline coronary angiography, IVUS data acquired by using a 20 MHz, 2.9F IVUS catheter were reconstructed by a VH-IVUS recorder (Volcano Therapeutics). Plaque components were categorized into four parts: fibrous (F), fibrofatty (FF), necrotic core (NC), and dense calcium (DC) areas.【Results】Plaques were detected in all the sites with LS, AN, and RA, while they were sometimes observed in N (10.3%). FF and NC areas were commonly found, in addition to F and DC areas (percentage of the area of each component in the plaque area, %F: 59.7 ± 2.3; %FF: 24.0 ± 2.2; %DC: 5.8 ± 1.0; %NC: 10.5 ± 1.2). Both %DC and %NC areas were significantly higher in LS, than in RA and in N (p < 0.05, respectively), while %F and %FF were similar among 4 lesions. Qualitatively, thin fibrous cap lesions with underlying NC were sometimes found in advanced lesions (LS, AN and RA).【Conclusions】These VH-IVUS findings give us a new insight into the potential role of atherogenesis in the evolution of CALs in the adolescents and young adults long after KD.