Abstract.We have developed a novel miniature integrated optical coherence tomography (OCT)-intravascular ultrasound (IVUS) probe, with a 1.5-mm-long rigid part and 0.9-mm outer diameter, for real-time intracoronary imaging of atherosclerotic plaques and guiding of interventional procedures. By placing the OCT ball lens and IVUS transducer back-to-back at the same axial position, this probe can provide automatically coregistered, coaxial OCT-IVUS imaging. To demonstrate its real-time capability, three-dimensional OCT-IVUS imaging of a pig’s coronary artery displaying in polar coordinates, as well as images of three major types of atherosclerotic plaques in human cadaver coronary segments, were obtained using this probe and our upgraded system. Histology validation is also presented.