**Abstract**

*Pseudomonas aeruginosa* is an opportunistic Gram-negative bacterium accountable for causing life-threatening infections in humans. According to the World Health Organization, *P. aeruginosa* classified as a critical pathogen. Specifically, *P. aeruginosa* in its colonized or biofilm state presents a major infection threat to immunocompromised (HIV) patients, Cystic fibrosis, burns, wounds and surgery associated infection. It is also a common pathogen responsible for causing hospital acquired/ nosocomial infection and Urinary tract infections. *P. aeruginosa* biofilm is made up of bacterial self-synthesized biomolecules includes extracellular DNA, polysaccharides, proteins, RNA, siderophores and metabolites such as pyocyanin. This chapter will elaborate the manifold functions of *P. aeruginosa* secreted biomolecules in establishing and stabilizing biofilms, triggering virulence and pathogenicity in host, and resisting antibiotics and antibacterial agents.

**Keywords:** *Pseudomonas aeruginosa*, pyocyanin, extracellular DNA, biofilms, alginate, rhamnolipids, pyoverdine
