Until today there are still a high percentage of oral microorganisms have not been identified due to inability to isolate using the cultural method. However, identification of uncultivable microorganisms associated with disease will permits clinicians for a more accurate diagnosis, treatment and preventive measures. Unculturable microorganisms are also involved in disease and may account for treatment failure since their susceptibility to antimicrobial agents would be unknown. Thus, the opportunity for a rational approach to the treatment of disease relies on the state of knowledge concerning its aetiology and pathogenesis. Recently developed molecular methods have made it possible to characterise mixed microflora in their entirety, including the substantial numbers of unculturable bacteria. The development of rapid molecular methods like PCR provides a reliable identification of unculturable microorganisms. This paper will review the current literature regarding the PCR techniques used to identify uncultivable oral microflora.