Brucellosis remains a significant zoonotic disease globally, with *Brucella abortus* being the most widespread form in cattle. *Brucella melitensis* is the primary cause of human brucellosis, particularly in the Mediterranean region, western Asia, and parts of Africa and Latin America. *Brucella suis* is emerging as a new source of infection in cattle, and *Brucella* strains have been isolated from marine mammals, expanding their ecological range. Molecular genetic studies have shown that *Brucella* is phylogenetically related to *Agrobacterium*, *Phyllobacterium*, *Ochrobactrum*, and *Rhizobium*. Pathogenicity is associated with the production of specific lipopolysaccharides, Cu-Zn superoxide dismutase, and stress-induced proteins. Diagnosis relies on organism isolation and serologic tests, with polymerase chain reaction (PCR) showing promise. Treatment involves tetracyclines, aminoglycosides, or quinolones, but no satisfactory vaccine is available. The complexity of *Brucella* strains and their interactions with hosts continues to challenge control and prevention efforts.Brucellosis remains a significant zoonotic disease globally, with *Brucella abortus* being the most widespread form in cattle. *Brucella melitensis* is the primary cause of human brucellosis, particularly in the Mediterranean region, western Asia, and parts of Africa and Latin America. *Brucella suis* is emerging as a new source of infection in cattle, and *Brucella* strains have been isolated from marine mammals, expanding their ecological range. Molecular genetic studies have shown that *Brucella* is phylogenetically related to *Agrobacterium*, *Phyllobacterium*, *Ochrobactrum*, and *Rhizobium*. Pathogenicity is associated with the production of specific lipopolysaccharides, Cu-Zn superoxide dismutase, and stress-induced proteins. Diagnosis relies on organism isolation and serologic tests, with polymerase chain reaction (PCR) showing promise. Treatment involves tetracyclines, aminoglycosides, or quinolones, but no satisfactory vaccine is available. The complexity of *Brucella* strains and their interactions with hosts continues to challenge control and prevention efforts.