Autotaxin (ATX), or nucleotide pyrophosphatase-phosphodiesterase 2, is a secreted lysophospholipase D that generates bioactive phospholipids that act on G protein-coupled receptors. Here we show the expression patterns of the ATX gene in mouse and chicken embryos. ATX has a dynamic spatial and temporal expression pattern in both species and the expression domains during neural development are quite distinct from each other. Murine ATX (mATX) is expressed immediately rostral to the midbrainhindbrain boundary, whereas chicken ATX (cATX) is expressed in the diencephalon and later in the parencephalon-synencephalon boundary. In the neural tube, cATX is expressed in the alar plate in contrast to mATX in the floor plate. ATX is also expressed in the hindbrain and various organ primordia such as face anlagen and skin appendages of the mouse and chicken. These results suggest conserved and non-conserved roles for ATX during neural development and organogenesis in these species. Developmental Dynamics 236: 1134 -1143, 2007.