Aim: to describe multidrug-resistant bacteria and their antimicrobial susceptibility patterns in ICU at Brazzaville University Teaching Hospital (CHUB). Materials and Methods: This was an observational, descriptive, and retrospective study, over 12 months, including all bacteria isolated in infected patients in ICU at CHUB. Epidemiological, clinical and bacteriological parameters were analyzed with Excel 2019. Results: 99 Bacteria were identified in 115 samples of 77 patients. Median age of patients was 48 years [32–65 years], 57.1% were females and acute generalized peritonitis represented 26% of diagnoses. Blood cultures (44.4 %), Gram-negative bacilli (77.7 %) were the most represented. E. coli (13.1%), K. pneumoniae (10.1%), A. baumannii (9.1%) and S. aureus (8.1%) were most bacteria identified. E. coli strains were extended-spectrum beta-lactamase (ESBL)- E. coli (82.4%) and carbapenem-resistant E. coli (86.4%). E. coli was resistant to third-generation cephalosporins (3GC) (86.1%), to fluoroquinolones (81.3%), to aminoglycosides (72.7%). ESBL-producing K. pneumoniae represented 76.1% and carbapenem-resistant K. pneumoniae represented 23.5% of K. pneumoniae strains. K. pneumoniae was resistant to piperacillin/tazobactam (83.3%), to aztreonam (71.4%), to quinolones (75.9%) and to aminoglycosides (66.7%). A. baumannii strains were resistant to Carbapenem (100%), to 3GC (100%), piperacillin/tazobactam (100%), aminoglycosides (92%), and quinolones (89.2%). S. aureus strains were Methicillin-resistant S. aureus in 75% and S. aureus strains were resistant to piperacillin/tazobactam (90.9%), vancomycin (88.9%), carbapenems (88.2%), 3GC (86%), quinolones (82.6%). Conclusion: The Multi-Drug-Resistant bacteria prevalence is very high in ICU at CHUB.