The bone morphogenetic proteins (BMPs) are members of the TGF beta superfamily of growth factors. We have investigated the effects of BMP-2, BMP-4, and BMP-6 on the development of quail trunk neural crest cells in tissue culture. The presence of human recombinant BMP-2 or BMP-4 resulted in a dramatic increase in the number of tyrosine hydroxylase (TH)-immunoreactive cells which developed after 7 days in vitro. In contrast, BMP-6 showed little or no effect. Total cell number was not altered significantly by BMP-2, BMP-4, or BMP-6. However, in the presence of BMP-2 and BMP-4, but not BMP-6, the fraction of the cell population that became melanocytes was reduced to about two-thirds the control value. Addition of BMP-2 and BMP-4 also increased the number of Islet-1-immunoreactive and Hu-immunoreactive cells, but the magnitude of these increases was less than that observed for the TH-immunoreactive cell population. The Islet-1-immunoreactive cells were a subset of the TH-immunoreactive cells, while the Hu-positive cells were distinct from the TH-immunoreactive population. Analysis using bromodeoxyuridine labeling indicated that the increased numbers of TH-immunoreactive cells observed in the presence of BMP-2 and BMP-4 were not due to an increased rate of cell division in committed TH precursors. Further experiments, in which cultures were initiated from single cells, showed that the presence of BMP-2 resulted in colonies containing numerous catecholamine-positive cells without altering the overall number of colonies which survived and developed. In summary, our findings indicate that BMP-2 and BMP-4 are potent regulators of the adrenergic development of avian trunk neural crest cells.