Biofilms are microbial communities quite different from planktonic cells and most of common microbiological concepts had to be updated in recent years. The peculiar capacity to resist to disinfectants and antibiotics results in biofilms being a public health problem mainly when modern medical devices are used. All artificial surfaces used in medicine may be prone to biofilm attachment and could therefore represent a cause of acute or chronic infectious diseases. Uremic patients are at higher risk from biofilms as not only traditional causes, such as indwelling catheters, but also hemodialysis apparatuses contribute to bacterial exposure. Chemical or physical disinfections have been demonstrated partially active on sessile microorganisms and biofilm avoidance remains the goal to assure an adequate quality of dialytic treatment.