JPEG2000 plays an important role in image data compression. However, JPEG-2000 produces noticeable image degradation, so-called “ringing artifacts,” in the vicinities of edges in reconstructed images, especially when the images are highly compressed. Ringing artifacts result in artificial contours, thus so degrading the quality of decoded images. To improve the visual quality of decoded images and make them perceptually acceptable, post-processing to accomplish de-ringing is often used. In this paper, an adaptive directional morphological filter (ADMF) to reduce ringing artifacts is presented. Compared with the previously proposed methods, ADMF is rather efficient and effective. Simulation results show that ADMF is capable of significantly reducing ringing artifacts.