Acinetobacter baumannii is a Gram-negative pathogen responsible for hospital- and community-acquired infections, particularly in immunocompromised patients. It is part of the ESKAPE group, known for its high genomic plasticity and ability to acquire and exchange mobile genetic elements (MGEs) through horizontal gene transfer (HGT), contributing to its antibiotic resistance and virulence. This review discusses the pan-genome and virulence factors of A. baumannii, highlighting its role as a global public health concern. The pan-genome of A. baumannii is open, containing a large number of MGEs such as insertion sequences, transposons, and integrons, which facilitate the acquisition of resistance genes. The genome of A. baumannii is highly variable, with a median length of 3.96 Mb and a G+C content of 39%. The pan-genome includes a core genome (shared by most strains) and an accessory genome (variable among strains), which contains genes involved in virulence, antibiotic resistance, and adaptation. The accessory genome is enriched with mobile genetic elements, contributing to the diversity of virulence factors and resistance mechanisms. A. baumannii possesses a wide range of virulence factors, including capsular exopolysaccharides (CPS), efflux pumps, lipopolysaccharides (LPS), lipooligosaccharides (LOS), outer membrane proteins (OMPs), pili, metal ion uptake systems, and secretion systems. These factors contribute to the bacterium's ability to survive in hostile environments, evade the immune system, and cause infections. The study also highlights the role of phages and plasmids in the dissemination of antibiotic resistance genes (ARGs) and the importance of understanding the pan-genome and virulence factors of A. baumannii for developing effective strategies to combat its global health threat.Acinetobacter baumannii is a Gram-negative pathogen responsible for hospital- and community-acquired infections, particularly in immunocompromised patients. It is part of the ESKAPE group, known for its high genomic plasticity and ability to acquire and exchange mobile genetic elements (MGEs) through horizontal gene transfer (HGT), contributing to its antibiotic resistance and virulence. This review discusses the pan-genome and virulence factors of A. baumannii, highlighting its role as a global public health concern. The pan-genome of A. baumannii is open, containing a large number of MGEs such as insertion sequences, transposons, and integrons, which facilitate the acquisition of resistance genes. The genome of A. baumannii is highly variable, with a median length of 3.96 Mb and a G+C content of 39%. The pan-genome includes a core genome (shared by most strains) and an accessory genome (variable among strains), which contains genes involved in virulence, antibiotic resistance, and adaptation. The accessory genome is enriched with mobile genetic elements, contributing to the diversity of virulence factors and resistance mechanisms. A. baumannii possesses a wide range of virulence factors, including capsular exopolysaccharides (CPS), efflux pumps, lipopolysaccharides (LPS), lipooligosaccharides (LOS), outer membrane proteins (OMPs), pili, metal ion uptake systems, and secretion systems. These factors contribute to the bacterium's ability to survive in hostile environments, evade the immune system, and cause infections. The study also highlights the role of phages and plasmids in the dissemination of antibiotic resistance genes (ARGs) and the importance of understanding the pan-genome and virulence factors of A. baumannii for developing effective strategies to combat its global health threat.