Epigenetic reprogramming is commonly defined as the erasure or removal of an existing set of epigenetic marks, followed by establishment of a different set of marks. Epigenetic reprogramming can occur in specific genes or subsets of genes, for example during lineage-specific differentiation events. It can also take place on a more global level, for example when primordial germ cells undergo erasure of histone marks and DNA methylation in many genes and sequences in the genome, or in the early embryo after fertilisation, where gametic epigenetic programmes are replaced by those characteristic of totipotent and pluripotent embryonic cells and stem cells. Experimental epigenetic reprogramming on a large scale has been shown to be possible during animal cloning, and during the recent spectacular direct reprogramming of differentiated cells to ES like cells. However, these advances have also highlighted the fact that natural reprogramming needs to be understood mechanistically so that the experimental techniques can be improved and made fully efficient for potential applications in regenerative medicine. Mechanistic insights are now aided by the recent development of genome-wide epigenomic profiling techniques for histone modifications, transcription factors, and DNA methylation. The purpose of this chapter is to provide a brief summary of how these technical advances are illuminating a fascinating area of biology with immense promise for medicine. [ABSTRACT FROM AUTHOR]