Aim: To estimate the prevalence and risk-factor of HAI after maxillofacial and oral surgery procedures in patients with combat-related head and neck injuries in Ukraine, and determine antimicrobial resistance of the responsible pathogens. Materials and Methods: A multicenter prospective observational cohort study was conducted from June 2022 to December 2025. Definitions of HAIs were adapted from the CDC/NHSN. Antibiotic susceptibility test of bacteria was determined according to the EUCAST. Results: Among 2,631 patients, 1,075 (40.9%) HAIs were observed. The most frequently reported HAIs were surgical site infections (54%), bone and joint infection (14.2%), pneumonia (12.2%), urinary tract infections (8.6%), bloodstream infections (6.6%), Eye, ear, nose, throat, or mouth infection (4.4%). Risk factor for HAIs were length of stay in ICU, type of injury, intubation, vascular and urinary catheters. The most pathogens isolated from HAIs were Escherichia coli (19.2%), Pseudomonas aeruginosa (7.6%), Klebsiella pneumonia (7.3%), Enterococcus faecalis (6.9%), Acinetobacter baumannii (6.6%), Staphylococcus aureus (5.5%), Serratia marcescens (5.5%). Meticillin resistance was reported in 36.1% of S. aureus, and 15.9% of enterococci were resistant to vancomycin. Resistance to third-generation cephalosporins was reported in 64.8% K. pneumoniae and in 43.6% E. coli. Conclusions: This study found a high prevalence of HAIs in patients with combat-related head and neck injuries who has undergone maxillofacial or/and oral surgery procedures, caused by MDROs, varying depending on the bacterial species, and antimicrobial group.