Background: We used virtual histology-intravascular ultrasound (VH-IVUS) to evaluate the relation between urine albumin excretion rate and plaque components in 920 patients. Methods: We divided the patients into two groups [microalbuminuria group (albuminuria >30 mg/ml/d, n=96) vs. normoalbuminuria group (n=824). VH-IVUS analysis classified the color-coded tissue into four major components: green (fibrotic); yellow-green (fibro-fatty); white (dense calcium, DC); and red (necrotic core, NC). Results: Microalbuminuria group was more hypertensives (75% vs. 57%, p=0.001) and more diabetics (53% vs. 26%, p<0.001) and had higher glucose (161짹50 vs. 133짹41 mg/dl, p<0.001), white blood cell count (8248짹2802 vs. 7241짹2411/mm3, p=0.002), fibrinogen (313짹91 vs. 264짹69 mg/dl, p<0.001), high-sensitivity C-reactive protein (1.2짹4.0 vs. 0.3짹0.6 mg/dl, p=0.029), NT-pro-BNP (1067짹3867 vs. 189짹343 pg/ml, p=0.035), and lower hemoglobin level (13.1짹1.6 vs. 13.5짹1.6 mg/dl, p=0.014) and lower left ventricular ejection fraction (61짹11 vs. 65짹7%, p=0.002). Microalbuminuria group had greater plaque plus media area at the minimum lumen site (11.9짹4.3 vs. 10.2짹4.0 mm2, p=0.001) and greater absolute NC and DC areas at the minimum lumen site (1.7짹1.3 vs. 1.2짹1.0 mm2, p<0.001, and 0.7짹0.6 vs. 0.6짹0.6 mm2, p=0.034, respectively) and greater absolute and %NC volumes (19.6짹24.1 vs. 14.0짹16.9 mm3, p=0.031, and 18.6짹9.3 vs. 16.5짹9.2%, p=0.039, respectively). Baseline urinary albumin-to-creatinine-ratio correlated positively with plaque plus media area at the minimum lumen site (r=0.083, p=0.012), absolute NC (r=0.130, p<0.001) and %NC (r=0.075, p=0.024) and absolute DC areas (r=0.072, p=0.030) at the minimum lumen site and absolute NC (r=0.210, p<0.001) and %NC (r=0.094, p=0.004) and absolute DC volumes (r=0.152, p<0.001). Conclusions: VH-IVUS analysis demonstrates that microalbuminuria at the time of clinical presentation was associated with more vulnerable plaque component.