Previous studies in the lab have shown that anterior-most floor plate cells undergo a change in fate in response to BMP-Tbx2 mediated signalling and give rise to ventral midline hypothalamic cells. In this study I have further characterised the ventral midline of the hypothalamus in the E4-E7 chick embryo. I demonstrate that the hypothalamic ventral midline is a complex structure comprised of distinct regions along its anterior-posterior axis. Fate-mapping studies demonstrate unequivocally that presumptive hypothalamic floor plate cells give rise to recognisable parts of the hypothalamus, In particular to the retrochiasmic, tubero-infundibular and mammillary regions and to distinct morphological structures, including the infundibulum and mammillary pouch.