We used Fgf10-lacZ reporter mice to investigate the distribution and fate of Fgf10-expressing cells in the developing and adult mouse brain. We find that the domain of Fgf10 expression expands post-natally and new niches emerge in the adult brain. Fgf10 is expressed in the adult cerebellum, thalamic, mid- and hindbrain nuclei and hippocampal CA fields, as previously reported in the rat brain. In addition though, we have discovered expression in: the hippocampal dentate gyrus; a discrete trail linking the ventral telencephalon with the olfactory bulbs; ventral ependyma of the third ventricle from where cells appear to disperse into the hypothalamus; and in the pituitary gland. Most Fgf10-expressing cells or their immediate descendants appear immature but a subset differentiates into neurons and glial cells. The manner in which Fgf10 is expressed in these active and quiescent neurogenic niches implicates it in control of neurogenesis and/or conservation of neurogenic potential.