Enterococcus faecalis KBL703 has three plasmids(p703/9, p703/5 and p703/4). Within p703/5, the specific DNA region that would confer replication function(replication origin) was searched by transformation experiments. In order to use as the recipient of transformation, two plasmid-cured strainsd were made from this strain. Four recombinant DNA constructs, each containing fragment of p703/5 and CAT(chloramphenicol acetyl transferase) gene were also made. And they were used to transform the plasmid-cured strains. Only one DNA construct containing 3.6 kb SalI fragment was stably maintained as plasmid in these strains. Additional experiment using another Enterococcus faecalis strain(ATCC29212) as a recipient was successfully done and it was confirmed that this newly constructed recombinant plasmid plasimid contained the replication origin from p703/5 plamid.