We assessed the progression of coronary atherosclerosis by comparing early to late fibroatheromas(FA) using virtual histology intravascular ultrasound(VH-IVUS) analysis of 114 coronary arteries from 40 autopsied cases of non-sudden cardiac death(NSCD). Results. Pt age was 46짹11yrs and 75% were males. Pt age was lower in early vs late FA(39짹7.6yrs vs 45짹11.6yrs,p=0.03). Greyscale IVUS showed difference in vessel size(7.09짹1.39mm2 vs 9.72짹2.39mm2,p=0.001) and lumen area(3.48짹1.08mm2 vs 4.48짹1.23mm2,p=0.003), but no difference in plaque burden(51.3짹7.3% vs 53.3짹8.8%,p=0.7) comparing early vs late FA. VH-IVUS showed relatively less fibrotic and fibrofatty plaque and relatively more dense calcium in late FAs. Furthermore, relative amounts of fibrotic and fibrofatty plaque decreased as necrotic core increased(r=0.786,p<0.0001 and r=0.464,p<0.0001), while the relative amount of dense calcium area increased as the size of the necrotic core increased(r=0.623,p<0.0001). Thus, small, early FAs with a small necrotic core had relatively less calcium than more advanced fibroatheromas with a large necrotic core. Conclusion. Late FA show more dense calcium than small, early FA. More studies are necessary to assess the role of calcium in fibroatheroma progression.