Metallothioneins(MTs) are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions.A cadmium metallothionein(EcMT-Cd) cDNA with a 189 bp open reading frame(ORF) that encoded a 62 amino acid protein was obtained from Exopalaemon carinicauda.Seventeen cysteines were in the deduced amino acid sequence,and the cysteine(Cys)-rich characteristic was revealed in different metallothioneins in other species.In addition,the deduced amino acid sequence did not contain any aromatic amino acid residues,such as tyrosine(Tyr),tryptophan(Trp),and phenylalanine(Phe).EcMTCd mRNA was expressed in all tested tissues(the ovary,muscle,stomach,and hepatopancreas),and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50μmol/L CuSO4or 2.5μmol/L CdCl2.The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4for 12 h and down-regulated in shrimps exposed to CdCl2for 12 h.After 24 h exposure to both metals,its expression was down-regulated.By contrast,at 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdCl2.The transcript of EcMT-Cd was very low or even absent before the zoea stage,and the expression of EcMT-Cd was detected from mysis larvae-I,then its expression began to rise.In conclusion,a cadmium MT exists in E.carinicauda that is expressed in different tissues and during different developmental stages,and responds to the challenge with heavy metal ions,which provides a clue to understanding the function of cadmium MT. Metallothioneins (MTs) are a group of low molecular weight cysteine-rich proteins capable of binding heavy metal ions. A cadmium metallothionein (EcMT-Cd) cDNA with a 189 bp open reading frame (ORF) that encoded a 62 amino acid protein was from Exopalaemon carinicauda. Seventeen cysteines were in the deduced amino acid sequence, and the cysteine ​​(Cys) -rich characteristic was revealed in different metallothioneins in other species. In addition, the deduced amino acid sequence did not contain any aromatic amino acid residues, such as tyrosine (Tyr), tryptophan (Trp), and phenylalanine (Phe) .EcMTCd mRNA was expressed in all tested tissues (the ovary, muscle, stomach, and hepatopancreas), and its expression profiles in the hepatopancreas were very different when shrimps were exposed to seawater containing either 50 μmol / L CuSO4or 2.5 μmol / L CdCl2. The expression of EcMT-Cd was significantly up-regulated in shrimp exposed to CuSO4 for 12 h and down-regulated in shrimps exposed to CdCl2 for 12 h. After 24 h exposure to both metals, its expression was down-regulated. At 48 h the EcMT-Cd was up-regulated in test shrimps exposed to CdCl2. The transcript of EcMT-Cd was very low or even absent before the zoea stage , and the expression of EcMT-Cd was detected from mysis larvae-I, then its expression began to rise. In conclusion, a cadmium MT exists in E. corinicauda that is expressed in different tissues and during different developmental stages, and responds to the challenge with heavy metal ions, which provides a clue to understanding the function of cadmium MT.