Abstract: Objective To analyze sequences of the housekeeping genes including recA,dnaE,and mdh in different serogroups or different biotypes of Vibrio cholerae(VC)strains isolated from China.Methods and Results recA,dnaE,and mdh genes of Vibrio cholerae were obtained by PCR,sequenced and analyzed.Forty-four variable bases were identified in the 500 bases of recA gene of 18 VC strains,and the mutation of only 3 variable bases could result in changes of 2 amino acids.In the 600 bases of dnaE genes of 18 strains,32 variable bases were found and only 1 contributed to an amino acid change.In the 67 bases of mdh genes of 18 strains,only 1 variable base was identified whose mutation involved an amino acid convertion.Toxic EI Tor biotype(EVC)strains and toxic O139 serogroup strains were closely related.Non-toxic strains of different serogroups or types were lowly related.Non-toxic and toxic strains of different serogroups or types were lowly related.Conclusion Toxic EVC and toxic O139 serogroup strains isolated from different areas of China may evolve from a common original strain,and toxic O139 VC strains may come from toxic EVC strains.