We assessed Virtual Histology Intravascular Ultrasound (VH-IVUS) plaque composition in pts with acute ST elevation myocardial infarction (STEMI). VH-TCFAs were defined as necrotic core (NC) >10% of plaque area, plaque burden >40%, and NC in contact with the lumen for ���3 image slices. Remodeling index (RI) was lesion/reference external elastic membrane >1.05. Results. 200 consecutive pts presented with STEMI. Pts age was 59짹11.74 yr in diabetes vs 59짹12.21 yr in non-diabetes, p=0.713). VH-IVUS imaging of the culprit lesion was performed in 172 pts who were divided into 2 groups: diabetes (38 pts) and non-diabetes (134 pts). The multivessel disease was 64%(24/38) in diabetes versus 61%(82/134) of non-diabetes(p=0.541), and % diameter stenosis was similar(73.81짹18.22 in diabetes vs 80.50짹18.72 in non-diabetes, p=0.109). Plaque rupture was present in 42% (17/38) diabetes vs 41% (55/134) non-diabetes (p=0.558). VH-TCFAs was present in 37% (14/38) diabetes vs 39% (52/134) non-diabetes(p=1.0). While vessel size, lesion length, plaque burden, minimal lumen area (MLA) and remodeling index were similar, average necrotic core (NC)(%) were larger in diabetes than non-diabetes(p=0.012)(Table). Conclusion. The nature of plaque is more necrotic but similar incidence of VH-TCFAs in diabetic STEMI. Further study is necessary to assess the factors responsible for increased risk in diabetes patients.