Abstract: Objective To study the molecular epidemiologic relationship and antibiotic resistances of salmonella serotype paratyphi A strains isolated from outbreak and sporadical cases in Hangzhou from 2002 to 2005.Methods Salmonella serotype paratyphi A strains were typed by pulse field gel electrophoresis(PFGE),and their antibiotic resistances were determined by disc diffusion test(Kirby-Bauer method).Results 4 PFGE patterns(A、B、C、D)were found in 15 isolates,and type A,B,and C were very close.All strains were 100% antibiotic resistance to SMZ-TMP and Rifampicin.No strain was resistant to cefazolin,ceftriaxone sodium,streptomycin,gentamycin,amikacin,chloramphenicol,norfloxacin,ciprofloxacin,furanzolidone.Four type strains were different antibiotic resistance to ampicillin,doxycycline and tetracycline.Conclusion S.paratyphi A strains isolated from two regions(county L and borough X)in Hangzhou from 2002 to 2005 were in the same clone family except one sporadical strain.Sporadical cases both followed outbreak epidemics in those two regions possibly.