Recent data indicate that the process of neurogenesis in the mammalian central nervous system (CNS) may be regulated by peptide growth factors, such as epidermal growth factor, transforming growth factor-alpha, and acidic or basic fibroblast growth factor. We have investigated whether members of the transforming growth factor-beta (TGFβ) family also play a role in this process and have found that TGFβ-3 is mitogenic for embryonic rat retinal cells in vitro. We also show that TGFβ-3 stimulates production of retinal amacrine cells while photoreceptor production remains unchanged. These data demonstrate that TGFβ-3 can regulate cell proliferation in the CNS during development and can also influence commitment or differentiation, or both, of neural progenitor cells to particular retinal fates. © 1995 John Wiley & Sons, Inc.