The study was conducted to describe antibiotic resistance characteristics and genotype correlation of 25 Serratia marcescens strains isolated in patients treated at 108 Central Military Hospital from 2014-2016. The results showed that there was an increase in antibiotic resistance of Serratia marcescens strains in this study for antibiotic groups such as fluoroquinolones, aminoglycosides, and extended-spectrum cephalosporins, which were commonly used for treatment of Serratia marcescens infection. The rates of resistance to cefotaxime (32%), ciprofloxacin (28%), gentamycin (24%), aztreonam (28%) and cefepime (12%) were higher than previous studies in the world such as in the US and Europe. Tweenty percent of Serratia marcescens isolates capable of producing ESBL carried bla CTX-M gene and 12% carried bla TEM gene. Analysis on genotype correlation by Pulsed-field gel electrophoresis (PFGE) technique showed that strains of the bacterium did not belong to a single genotype, there were three genotypes S1, S2, S3 identified with similarity of ≥85%, and the possible hypothesis about the spread of bacterial infections between departments in the hospital existed.