Eukaryotic elongation factor 1α(EF-1α)plays an important role in translation and its sequence is highly conservative as a housekeeping gene.The partial cDNA encoding EF-1α in Oreochromis aureus was isolated using RT-PCR.The cDNA encoding 141 amino acids with a calculated molecular weight of 15.1 ku was 425 bp.The comparison of the deduced amino acid sequence of O.aureus EF-1α with that of O.niloticus,Oryzias latipes,Dicentrarchus labrax,Danio rerio or Salmo trutta showed that the homology rates were 100%,92%,91%,85%,and 82%,respectively,while the amino acids homology was 85% when comparing O.aureus with Mus musculus,Homo sapiens,Gallus gallus,or Rattus norvegicus.The DNA sequence of O.aureus EF-1α consisting of 506 bp was also cloned.Comparing the partial cDNA to its genomic sequence revealed that O.aureus EF-1α gene consisted of an intron,which supplied useful information in designing the EF-1α primer in real time RT-PCR and calculating the EF-1α expression in different tissues.