BM2 monoblasts constitutively express v-myb oncogene and their terminal differentiation steps are blocked. However, using phorbol esters the terminal differentiation can be resumed. We wished to explore the role of p53 in regulation of differentiation, proliferation and apoptosis of BM2 cells. We inducibly expressed human p53 in chicken BM2 cells. Upon stabilization using roscovitine the p53 protein was capable to suppress growth and induce terminal differentiation of BM2 cells.