A 467 bp full-length cDNA sequence of metallothionein(named as HCMT) gene was obtained using rapid amplification of cDNA end(RACE) technique in Hyriopsis cumingii.It consists of a 92 bp 5′ untranslated region(UTR),a 216 bp open reading frame(ORF) and a 159 bp 3′UTR.The translated protein was composed of 71 amino acids,with a molecular weight of 7.1 ku,and its calculated isoelectric point was 7.24.The contents of cysteine and glycine in the predicted HCMT amino acid sequence were 29.6% and 14.1%,respectively.The conserved motif CKCXXXCXCX of molluscan MT was also found in HCMT.A specific pattern of molluscan MT C-X-C-X(3)-C-T-G-X(3)-C-X-C-X(3)-C-X-C-K was located at the C-terminal.The predicted protein sequence analysis showed that the MT of H.cumingii had the typical characteristics of MT family and shared a high similarity with that of other molluscans.