Indirect illumination is an important visual cue which has traditionally been neglected in mixed reality applications. We present Delta Light Propagation Volumes, a novel volumetric relighting method for real-time mixed reality applications which allows to simulate the effect of first bounce indirect illumination of synthetic objects onto a real geometry and vice versa. Inspired by Radiance Transfer Fields, we modify Light Propagation Volumes in such a way as to propagate the change in illumination caused by the introduction of a synthetic object into a real scene. This method combines real and virtual light in one representation, provides improved temporal coherence for indirect light compared to previous solutions and implicitly includes smooth shadows.