By the present time, a number of articles has been published testifying an extremely high potential of proteome of saliva for diagnostic of many diseases. At the same time, the conclusions can be made from these publications. In particular, to the effect that studies of proteome of saliva are at the stage of data accumulation only. Then, lacking of standardization in collection of samples, techniques of analysis and requirements to representativeness of samplings used as basis for conclusions carry in discrepancies into results acquired by different researchers. Furthermore, physiology and biochemistry of saliva are studied insufficiently as well as characteristics of interaction of proteins of saliva with micro-organisms of oral cavity. All of this establishes obstacles for implementations of achievements in studying of proteome of saliva in diagnostic practice. The solution of these problems will permit making saliva an ideal biological medium for both detection of diseases and prognosis of their course.