The article discusses the mechanisms of antimicrobial resistance in biofilms, which are communities of bacteria aggregated within a self-produced matrix. Biofilms exhibit significant physiological changes compared to planktonic bacteria, leading to chronic and antibiotic-resistant infections. The review covers the biofilm lifecycle, phenotypic characteristics, and the role of the extracellular matrix in resistance. It also explores how biofilms evolve antibiotic resistance and transfer resistance genes within and between species. Multispecies biofilms and the interactions between species, including cooperation and competition, are discussed, highlighting their impact on antimicrobial susceptibility. The matrix acts as a protective barrier, hindering antibiotic penetration and providing a reservoir for plasmid persistence and horizontal gene transfer (HGT). HGT, facilitated by biofilms, is a major contributor to the AMR crisis, with conjugation being the most significant mechanism. The article emphasizes the importance of understanding and studying resistance, tolerance, and persistence in conjunction to address AMR effectively.The article discusses the mechanisms of antimicrobial resistance in biofilms, which are communities of bacteria aggregated within a self-produced matrix. Biofilms exhibit significant physiological changes compared to planktonic bacteria, leading to chronic and antibiotic-resistant infections. The review covers the biofilm lifecycle, phenotypic characteristics, and the role of the extracellular matrix in resistance. It also explores how biofilms evolve antibiotic resistance and transfer resistance genes within and between species. Multispecies biofilms and the interactions between species, including cooperation and competition, are discussed, highlighting their impact on antimicrobial susceptibility. The matrix acts as a protective barrier, hindering antibiotic penetration and providing a reservoir for plasmid persistence and horizontal gene transfer (HGT). HGT, facilitated by biofilms, is a major contributor to the AMR crisis, with conjugation being the most significant mechanism. The article emphasizes the importance of understanding and studying resistance, tolerance, and persistence in conjunction to address AMR effectively.