Detection and identification of plant pathogens is one of the most important strategies for sustainable plant diseases management. For this reason, the availability of fast, sensitive and accurate methods for detection and identification of plant pathogens is increasingly necessary to improve disease control decision making process. In other words, new technologies and improved methods with reduced/fair cost and improved speed, throughput, multiplexing, accuracy and sensitivity have emerged as an essential strategy for the control of both fungal and bacterial diseases. The development of recombinant DNA technology is also possible to isolate individual genes and incorporate resistance genes into otherwise agronomically acceptable cultivars to develop genetically resistance variety for a particular disease. These advances have been complemented by the development of new nucleic acids extraction methods, increased automation, reliable internal controls, multiplexing assays, online information and on site molecular diagnostics. The different types of polymerase chain reaction (PCR) are the most common DNA amplification technology used for detecting various plant pathogens. With the applications of bioinformatics as a modern technology in plant pathology, identification of specific motifs, DNA sequences has become possible, which ultimately increase the accuracy of modern techniques in plant disease diagnosis. The newly emerged proteomic technology is also a promising tool for providing information about pathogenicity and virulence factors that will open up new possibilities for plant disease diagnosis and appropriate protection measures.