Grasshopper semaphorin I (Sema I) and its related proteins, chick collapsin and mouse Sema III contribute to the axon guidance by their repellent actions [5,9,12]. We have identified a member of semaphorin gene family from the mouse brain and named it M‐Sema F. The N‐terminal encodes a semaphorin domain that is similar between Sema I–III [6] followed by a single putative immunoglobulin‐like domain, a transmembrane domain, and a proline‐rich intracellular domain. M‐Sema F mRNA is expressed widely in the nervous tissues during development. These suggest that M‐Sema F is a transmembrane member of the semaphorin family of the vertebrate which may function in the developing neuronal network.