Angle-resolved photoemission experiments from ferromagnetic surfaces using circularly polarized x-ray and VUV radiation show pronounced magneto-dichroic effects. This "magnetic circular dichroism" (MCD) appears in photoemission from valence bands and core levels. It is attributed to the interplay of spin-orbit coupling and exchange interaction in the occupied electronic states. The effect of MCD in photoemission has potential applications as a new analytical tool in investigations of surface magnetism.