Saliva is a complex and dynamic fluid covering the entire surface of the oral cavity. Saliva is composed of water, inorganic and organic components produced by the host. In addition, saliva contains resident microbiota released from the oral niches as dental, tongue or mucosal sites. Salivary fluid provides a specific environment for planktonic microorganisms and the biofilms formed on oral niches. Therefore, saliva plays an essential role in oral biofilm formation. The biofilm model mimics natural biofilm might use saliva in the experimental design adapted to the research goal. This chapter describes the properties of the saliva associated with oral biofilm, saliva interaction with the oral niches harboring biofilm, and the use of saliva in the biofilm model as the source of microorganisms, growing medium and acquired pellicle.