INTRODUCTION Even though primary angioplasty has improved survival in STEMI patients as compared to thrombolysis, there is still room for improvement. Intravascular imaging may potentially provide further benefits in this setting. In fact, coronary angiography, historically the “gold standard,” has several limitations, because it does not provide information on quantity of plaque and its composition, true lumen diameter, and has low sensitivity in detecting intracoronary thrombus, plaque rupture, and suboptimal stent implantation. Several techniques have been recently proposed, with strengths and limitations (Table 1). The aim of the chapter is to review current potential application of intracoronary imaging in STEMI.