The full-length cDNAs of two novel T-superfamily conotoxins, Lp5.1 and Lp5.2, were cloned from a vermivorous cone snail Conus leopardus using 3′/5′-rapid amplification of cDNA ends. The cDNA of Lp5.1 encodes a precursor of 65 residues, including a 22-residue signal peptide, a 28-residue propeptide and a 15-residue mature peptide. Lp5.1 is processed at the common signal site -X-Arg- immediately before the mature peptide sequences. In the case of Lp5.2, the precursor includes a 25-residue signal peptide and a 43-residue sequence comprising the propeptide and mature peptide, which is probably cleaved to yield a 29-residue propeptide and a 14-residue mature toxin. Although these two conotoxins share a similar signal sequence and a conserved disulfide patte with the known T-superfamily, the pro-region and mature peptides are of low identity, especially Lp5.2 with an identity as low as 10.7% compared with the reference Mr5. 1a.The elucidated cDNAs of these two toxins will facilitate a better understanding of the species distribution,the sequence diversity of T-superfamily conotoxins, the special gene structure and the evolution of these peptides.