Abstract: Objective To clone A73 gene of Epstein-Barr virus (EBV) and examine the variation of its coding sequence. Methods A73 coding sequence (CDS) amplified from 7 patients in nasophryngeal carcinoma (NPC) biopsies by RT-PCR was cloned into pGEM-T-Easy vector to construct the recombinant plasmid, which was subjected to sequence analysis in Gen Bank database using Blast software. Results A73 gene from nasophryngeal carcinoma was successfully cloned into pGEM-T Easy vector. A locus with conversion of A→C in A73 was found at CDS 45 nt, located in the exonVB157154 nt, which did not result in an amino acid replacement, and the variation frequency was 7/7. Conclusion There is a point mutation in A73 CDS of EBV isolated from NPC tissue, which might produce NPC-associated polymorphism with possible invotvement in the composition of some subtype of EB virus.