The understanding on the plant genome is accelerated with the fast advance of molecular biological techniques. The molecular dissecting of the plant genome has made possible the precise genotyping the plants, which can be utilized for molecular breeding program. As well, the molecular cloning of genes interested can facilitate the process of gene transfer between intra-and inter-generic taxa. Moreover, the manipulation of the agronomically important QTL genes, which can be rarely performed by the conventional genetic methods, is also possible by the utilization of molecular markers. In addition to these genetical applications, molecular markers are useful in the areas of plant taxonomy and management of germplasm by fingerprinting analysis. This paper describes the theoretical aspects marker technologies and practical applications of each marker technique.