During development, co-ordinate regulation of cell cycle exit and differentiation of neuronal precursors is essential for generation of appropriate number of neurons and proper wiring of neuronal circuits. Recent studies have identified some of the molecules implicated in the regulation of these cellular events, but the complex machinery that orchestrates these processes into a coherent developmental program remains unclear. BM88/Cend1 is a neuronal protein associated in vivo with terminal neuron-generating divisions, marking the exit of proliferative cells from the cell cycle. Genetic studies in neural cell lines, neural stem/progenitor cells using the neurosphere system and in the developing chicken neural tube in vivo have shown that BM88/Cend1 is a dual function molecule co-ordinating cell cycle exit and differentiation of neuronal progenitors. These studies have thus shed light on a molecular determinant that participates, along with other known and possibly still unknown regulators, in the complex processes by which a progenitor cell becomes a mature neuron.