Biofilms are complex aggregates of microbes which attach to each other or to the surface and play a role in antibiotic resistance and persistence of infection. This research highlights that bacteria isolated from surface samples and equipments indicate poor hygienic condition in hospitals. Biofilm formation results in persistence of these organisms which contribute to Nosocomial infections. Contamination of water from swimming pools and domestic water indicates poor hygienic standards and ineffective chlorination. Biofilm of uropathogens and pus from wounds of diabetic patients, burn patient and surgical site infection result in prolonged infection, antibiotic resistance, delayed wound healing and extended hospitalization. Candida biofim also cause persistence of infection and helps the fungi to survive resulting in resistant infections. This book is useful for researchers, scientists, medical students, doctors and general public as it gives an insight about biofilms and its role in Nosocomial infection, transmission of infection through recreational water, domestic water and the role of biofilm in disease process and antibiotic resistance of organisms.