Transforming growth factor beta (TGF-beta) signaling has diverse and complex roles in various biological phenomena such as cell growth, differentiation, embryogenesis and morphogenesis. ES cells provide an essential model for understanding the role of TGF-beta signaling in lineage specification and differentiation. Recent studies have suggested significant role of TGF-beta in stem/progenitor cell biology. Here in this review, we focus on the role of the TGF-beta superfamily in neuronal development.