Whereas it is known that voltage-gated calcium channels play important roles during development, potential embryonic roles of voltage-gated sodium channels have received much less attention. Voltage-gated sodium channels consist of pore-forming α-subunits (Nav1) and auxiliary β-subunits. Here, we report the embryonic and larval expression patterns for all eight members of the gene family (scna) coding for zebrafish Nav1 proteins. We find that each scna gene displays a distinct expression pattern that is temporally and spatially dynamic during embryonic and larval stages. Overall, our findings indicate that scna gene expression occurs sufficiently early during embryogenesis to play developmental roles for both muscle and nervous tissues. Developmental Dynamics 235:1962–1973, 2006. © 2006 Wiley-Liss, Inc.