Optical coherencet tomography (OCT) is a light-based imaging modality that can provide in vivo high-resolution images of the coronary artery. In the last years there has been a continuous technical development that has improved the image quality and has simplified the acquisition procedure in order to spread the clinical applicability of this technique. Due to its high resolution OCT, can be a very valuable tool for the evaluation of the coronary vessel wall, the acute and long-term impact of catheter-based intervention on plaque structure and vessel architecture and the assessment of stents. During stenting, OCT offers the possibility to evaluate stent apposition in great detail and can identify the presence of vessel injury due to stent implantation. At follow-up, the tissue coverage of individual struts can be imaged with OCT. This is of increasing interest in drug-eluting stents in which the neointimal proliferation is inhibited to such extent that it might not be visualized with conventional intracoronary imaging techniques such as IVUS. Regarding the analysis of the coronary vessel wall, OCT holds promise for the identification of thin cap fibroatheroma due to its ability to provide information about plaque composition, presence of macrophages and thickness of the fibrous cap.