Nucleotide sequences of four cDNA clones coding for the carboxy-terminal portion of at least two different B1 hordein polypeptides are presented. The open reading frame in the nucleotide sequence of the the largest clone (pc hor2-4, 720 nucleotides) translates into the 181 carboxy-terminal amino acids of a polypeptide chain showing close homology to the previously determined primary structure of B1 hordein peptides. Of the 74 amino acid residues which can be compared 61 proved to be identical. The second cDNA clone (pc hor2-3, 257 nucleotides) encodes the 54 carboxy-terminal amino acids of a different B1 hordein polypeptide, which is revealed by 21 nucleotide substitutions resulting in 9 amino acid changes. The two other analysed cDNA clones contained sequences of 54 and 41 nucleotides respectively for the carboxy-terminal end of the same B1 hordein polypeptide as that coded for by pc hor2-3. The latter two clones (pc hor2-1, 254 nucleotides and pc hor2-2, 153 nucleotides) comparised the entire 3′ noncoding region of the B1 hordein messenger RNA including a poly(A) tail. Clone pc hor2-2 measures 99 nucleotides between between the stop codon and the poly(A) tail. A putative polyadenylation signal AATAAA is located 15 residues upstream from the poly(A) site. These 99 nucleotides of the 3′ noncoding region are extended by a sequence of 63 nucleotides in clone pc hor2-1. This additional sequence contains two AATAAA sequences located 13 and 24 nucleotides respectively from its poly(A) tail.