This study was carried out to investigate the extent of antibiotic resistance in catfish isolates (157 E. coli, 116 Pseudomonas spp. and 92 Aeromonas spp.) and 72 human E. coli isolates in Vietnam, including their resistance profiles to 14 antibiotics using the disk diffusion method, prevalence of class 1 and class 2 integrons using PCR and sequencing, and the roles of integrons in dissemination of resistance genes among the isolates. High levels of resistance to common antibiotics, such as ampicillin, tetracycline, trimethoprim/sulfamethoxazole and streptomycin were observed in both catfish and human isolates. Interestingly, catfish E. coli and human E. coli isolates had similar resistance patterns. Class 1 intergrons were detected in all sources, and the gene cassette arrays of dfrA1-aadA5 and dfrA12-orfF-aadA2 are the most prevalent among catfish and human isolates. The frequencies of untypical class 1 integrons, lacking the normal 3’-conserved segment, were high (67.1% and 37.5% integron positive catfish and human isolates respectively). In addition, transmission of class 1 integrons was demonstrated amongst isolates, including catfish isolates to human isolates, confirming their significant roles in dissemination of antibiotic resistance. To our knowledge, this is the first report on the molecular characterisation of antibiotic resistant bacteria isolated from catfish in Vietnam and the comparison of antibiotic resistance profiles of isolates from humans and non-humans sources. This study provided evidence of the dissemination of antibiotic resistance in bacteria isolated from environmental and clinical sources in Vietnam.