In order to improve the health-promoting activity of lactic acid hacteria, a good industrial host lactic acid bacterium and a good cloning vector is the prereyuisitc. Lactohacillus casei 102S, a known host strain, and Lactohacillus acidophilus HY7001, an established industrial strain, hove been examined for host strains of lactobacilli for research and industrial purposes, and a cloning vector plasmid, pNZ123, is tested for its stability in L casei 1025 and L acidophilus HY7001. The cells of these two lactobacillus strains from the logarithmic growth phase in LCM at 37℃ have been successfully transformed with plasmid pNZ123 by electroporation with 1100 voltage of electrical shock. The transformed cells of L casei 102S and L acidophilus HY7001 produced normal shapes of colonies on LCM agarplates and exhibited the chloramphenicol resistance phenotypes from pNZ123. Plasmid DNA of trenaformed L rasei 1025 and L acidnphikc.s HY7001 evidenced the bands of pNZ 12 3 on the agarose gel after electrophoresis. Bacteriocin plasmid, pIND. didn`t seem to transform any lactobacillus tested and any transformants of L casei 102S or L acidophilus HY7001 with pIND could not he isolated on the LCM agar plates after cotransformation attempt with pBS19, pBS100, or pNZ123.