Background: Ear, nose, and throat (ENT) inflammatory diseases are common conditions that account for a high proportion of healthcare visits. These diseases negatively affect patient’s quality of life, reduce work and learning capacity, and increase healthcare costs. Antibiotics play a crucial role in treatment; however, inappropriate use contributes to the emergence and spread of antimicrobial resistance among pathogenic bacteria. In Mongolia, particularly in Darkhan-Uul Province, data on bacterial pathogens and their antimicrobial susceptibility patterns in ENT infections are limited. Therefore, evaluating the local prevalence of methicillin-resistant Staphylococcus aureus (MRSA) and antimicrobial resistance is essential for guiding clinical practice and promoting rational antibiotic use. Aim: To assess the bacterial pathogens and their antimicrobial susceptibility patterns in inflammatory diseases of ear, nose and throat. Materials and Methods: The study was conducted at the School of Biomedicine, Mongolian National University of Medical Sciences, in collaboration with the Department of Pharmacology and the “Bid” Hospital of Darkhan-Uul Province. Data from ear, nose, and throat swab examinations of patients suspected of having ENT infections in the outpatient department between January 2024 and February 2025 were extracted from the hospital’s centralized database (n=185). Based on the inclusion and exclusion criteria, information from 145 patients was analyzed. The study was designed as a facility-based, retrospective, cross-sectional observational study and was carried out using SPSS - 26.0. Result: A total of 145 patients aged 1-73 years were included in the study, of whom 48.2% (n=70) were male and 51.7% (n=75) were female. Overall, 145 clinical specimens were collected, including nasal swabs 36 (24.8%), throat swabs 56 (38.6%), and ear swabs 53 (36.6%). Bacteriological examination revealed pathogenic microorganisms in 80.7% (n=117) of the specimens. S.aureus was isolated from 65.5% of nasal swabs, 53.6% of throat swabs, and 67.4% of ear swabs. Among S. aureus isolates from ear swabs, 27.6% (n=8) were identified as methicillin-resistant Staphylococcus aureus (MRSA). Antimicrobial susceptibility testing showed that S. aureus isolates from nasal swabs were resistant to amoxicillin (100%), ampicillin (90.0%), erythromycin (87.5%), and azithromycin (81.8%), while they were susceptible to cefazolin (72.7%), doxycycline (80.0%), and vancomycin (75.0%). S. aureus isolates from throat swabs demonstrated resistance to amoxicillin (100%), ampicillin (100%), chloramphenicol (87.5%), and azithromycin (75.0%), but were susceptible to ciprofloxacin (69.2%) and vancomycin (66.7%). S. aureus isolates from ear swabs were resistant to gentamicin (77.8%), clarithromycin (71.4%), azithromycin (66.7%), and penicillin G (66.7%), while higher susceptibility was observed to nitrofurantoin (87.5%), vancomycin (68.8%), and ciprofloxacin (64.7%). For Streptococcus spp, resistance was observed to erythromycin (84.6%), amoxicillin (76.9%), and chloramphenicol (71.4%), whereas susceptibility was noted to amoxiclav (54.6%), cefazolin (63.2%), and cefotaxime (50.0%). Conclusion 1. Staphylococcus aureus predominated in samples from ear, nose, and throat infections, confirming it as the main causative bacterium of these conditions. 2. The predominantly isolated Staphylococcus aureus showed high resistance to antibiotics from the penicillin, macrolide, and aminoglycoside groups.