Optical coherence tomography (OCT) is a novel invasive imaging technique that produces high resolution intracoronary images. Its general principle of operation is similar to IVUS, however OCT uses infrared light, not ultrasound. In the last years, the need for more precise information regarding coronary artery disease to achieve optimal treatment has seen intravascular imaging becoming an area of primary importance in interventional cardiology. OCT in this area has grown and is spreading. It benefits both therapeutic and research purposes and is also proving able to fill gaps in conventional invasive coronary imaging.