The zinc finger transcription factor Castor plays a pivotal role during neurogenesis in the fruit fly Drosophila melanogaster. Here, we report the expression pattern of a murine Castor related gene (Cst) during embryogenesis. Cst expression is first detected at E8.0 in the developing heart where its expression is maintained throughout development. By E8.5, Cst expression starts in the lateral neural folds of the hindbrain and extends anteriorly and posteriorly to eventually cover the dorsal neural tube from the isthmus to its caudal end. From E9.5, Cst transcripts can also be detected in the dorsomedial telencephalon. In the hindbrain, Cst expression is confined to trigeminal motor neurons and to migrating facial branchiomotor neurons. In the peripheral nervous system, Cst is expressed in cranial and in dorsal root ganglia. Cst expression is also observed in the developing eye and in the nasal placode.