Nkx-2.1 is a member of the vertebrate Nkx family of homeobox genes; it was originally identified as a tissue-specific regulator of thyroglobulin and thyroperoxidase gene transcription. Here we report on the embryonic expression of Xnkx-2.1, which is expressed in the presumptive forebrain from early neurulation onwards. In tadpole stage embryos Xnkx-2.1 transcripts are primarily detected in ventral forebrain, lung buds and thyroid anlage. Therefore, Xnkx-2.1 may be part of the genetic network that controls the early development of these organs.