Cell fate is determined by extracellular signals which are transmitted to the nucleus and result in the transcriptional regulation of specific subsets of genes. Transcriptional regulation has been recently linked to enzymatic activities which are able to acetylate or deacetylate core histone tails. A number of transcriptional co-regulators are histone acetyltransferases or histone deacetylases. Here, we discuss the involvement of these enzymes in critical steps of cell proliferation or cell differentiation control.