Endophytic fungi and bacteria are ubiquitous and occur within all known plants, including a broad range of hosts in various ecosystems, and therefore play an important role in the natural environment. Million species of endophytic fungi and bacteria are present in plant tissues. Nevertheless, our recognition of endophyte diversity is limited at present. In surveys of endophyte diversity, traditional techniques, such as culture-dependent methods, have been routinely used in since long. The discovery of endophytes in natural environments, however, has been limited by traditional methodology due to some non-culturable endophytes. Molecular techniques, such as DNA fingerprinting and sequencing methods, have been successfully employed in the detection and identification of endophytes fungi, and different endophyte diversity and community composition have been documented by cultivation-dependent and molecular techniques. This chapter summarizes the use of molecular fingerprinting protocols in the study of endophytic fungi and bacteria.