Background: We compared the plaque components at coronary sites with focal spasm after ergonovine provocation test in 30 variant angina (VA) patients with those at culprit coronary sites in 32 unstable angina (UA) patients using virtual histology-intravascular ultrasound (VH-IVUS). Methods: VH-IVUS classified and color-coded tissue into four major components: fibrotic; fibro-fatty; dense calcium (DC); and necrotic core (NC). Thin-cap fibroatheroma (TCFA) was defined as a NC ���10% of plaque area in at least 3 consecutive frames without overlying fibrous tissue in the presence of ���40% plaque burden. Results: The lesion site plaque burden was significantly smaller (44.5짹10.8% vs. 70.5짹13.1%, p<0.001), the plaque volume was significantly smaller (135짹118 mm3 vs. 223짹160 mm3, p=0.020), the remodeling index was significantly lower (0.90짹0.14 vs. 0.97짹0.23, p=0.023), and more plaque was hypoechoic with less calcium (87% vs. 56% and 0% vs. 19%, respectively, p=0.033) in VA patients compared with UA patients. The % NC and DC areas were significantly smaller at the minimum lumen site within spasm/culprit lesion (12.9짹12.9% vs. 22.3짹11.7%, p=0.004, and 6.5짹8.0% vs. 12.8짹10.8%, p=0.011, respectively), and the % NC and DC volumes were significantly smaller in VA patients compared with UA patients (12.2짹10.3% vs. 17.7짹8.1%, p=0.025, and 6.4짹11.8% vs. 6.0짹8.5%, p=0.007, respectively). The TCFA within lesion segments was less frequently observed in VA patients compared with UA patients (13% vs. 53%, p=0.001). Conclusions: VA patients have less plaque, more negative remodeling behavior, more hypoechoic plaque with less calcification, and less NC- and DC-containing lesions and less TCFA lesions compared with UA patients.