We present a three-dimensional (3-D) endoscopic optical coherence tomography (OCT) system using a dual axis scanning mirror. The MEMS device employed in this study utilized a 1.2 mm mirror and exhibited x and y-axis resonant frequencies greater than 1 kHz. The developed probe was packaged and integrated with an OCT system which has a scan rate of 3∼8 frames/s. Preliminary in vivo and in vitro 3-D OCT images of biological tissue, such as human finger, vocal cord, rabbit trachea, were visualized to verify the achieved performance of the device.