Rhizobacteria and endophytic bacteria  in the acid sulphate rhizosphere soils and stems/roots of sweet potatoes  grown on acid-sulphate soils  of the Mekong Delta, Vietnam  were  studied. A total of  96  isolates were isolated on two media (Burk’s N-free and NBRIP)  and 260 endophytic isolates  (128  isolates  from  LGI  medium  and  132  isolates  from  Nfb medium) from  60 rhizosphere soil  samples were taken in  three  regions (Tu Giac Long Xuyen, Dong Thap Muoi, Trung Song Hau) and all of them  have  ability  of  nitrogen  fixation  and  phosphate  solubilization. The  sequences  from  selected  rhizobacteria  and  endophytic  bacterial isolates (12 isolates) were analysed 16S rRNA gene fragmentsamplified from DNA using eubacterial universal primers (8F and 1492R) and sequenced. The results showed they had high degrees of similarity to those of the GenBank references strains (between 98% and 99%). From 12  isolates,  3  belonged to Bacilli while  Beta-proteobacteria and Gamma-proteobacteria were  3 and 6  strains,  respectively .  From these results showed that there  are  six  strains  as  Pseudomonas  taiwanensis  LA1-3-3,  Bacillus  circulans  KG2-3-2, Klebsiella sp. HG5-3-2, Enterobacter asburiae KG9-2-1-1, Burkholderia metallica HG7-2-1-2,  Enterobacter cloacae  AG1-1-1-1  revealed promising candidates  with multiple beneficial characteristics  and  they  have  the  potential  application  as  inoculants  adapted  to  poor  soils  (unfertile  soils)  and  local  crops  because  they  are  not  only  famous  but  also  safe  strains  for sustainable  agriculture,  especially  for  growing  sweet  potatoes  on  acid  sulphate  soils  in  the future.