Optical coherence tomography (OCT) is a coronary artery imaging technique with high resolution. Second-generation frequency-domain OCT (FD-OCT) technology allows safer and faster clinical application compared with first-generation time-domain OCT (TD-OCT). Only limited validation studies compare FD-OCT with other modes of analysis: histology, which is the current gold standard, and intravascular ultrasound (IVUS). This study therefore aims to demonstrate the accuracy of FD-OCT images compared with IVUS and histology. FD-OCT and IVUS images were acquired from 203 segments from 31 coronary arteries obtained at autopsy from 20 cadavers. Of these, 30 randomly-selected pairs were used to create three classifications of plaque type based on morphological features in FD-OCT and IVUS compared with corresponding histopathology. The remaining 173 pairs were used to demonstrate the diagnostic accuracy for classification of coronary plaques by FD-OCT. Plaque type distributions were 27% fibroatheroma, 22% fibrocalcific plaque and 51% fibrous plaque. The diagnostic accuracies of FD-OCT for fibroatheroma, fibrocalcific plaque and fibrous plaque were 90, 95 and 93%, respectively. Those of IVUS were 81, 89 and 84%, respectively. FD-OCT achieved high diagnostic accuracy for the classification of coronary plaques comparable to TD-OCT. Physicians should consider the differences in the ability to classify plaque morphology of OCT of imaging devices when applying their use.