Allatostatins with the C‐terminal ending Tyr/Phe‐Xaa‐Phe‐Gly‐Leu/Ile‐amide (FGLa/ASTs) are widespread neuropeptides with multiple functions. The gene encoding the FGLa/AST polypeptide precursor was first isolated from cockroaches and since then could be identified in many insects and crustaceans. With its strictly conserved regions in combination with variable regions the gene seems to be a good candidate for phylogenetic analyses between closely and distantly related species. Here, the structure of the FGLa/AST gene of the most primitive termite, the giant northern termite Mastotermes darwiniensis Froggatt, was identified. The FGLa/AST gene of the woodroach Cryptocercus darwini was also determined. Precursor sequences of both species possess the general organization of dictyopteran FGLa/AST precursors containing 14 putative FGLa/AST peptides. In M. darwiniensis, only 11 out of the 14 FGLa/AST‐like peptides possess the C‐terminal conserved region Y/FXFGL/I/V/M and four of the putative peptide structures are not followed by a Gly residue that would lead to nonamidated peptides. Phylogenetic analyses show the high degree of similarity of dictyopteran FGLa/AST sequences. The position of termites, nested within the Blattaria, confirms that termites have evolved from primitive cockroaches.