Phytoplasmas are phytopathogenic prokaryotes of great importance because they have been linked to numerous diseases around the world. The aim of these research was to present the general characteristics, the size and composition of the genome and the genes and/or regions used as molecular markers for the identification and characterization of phytoplasmas. Among its main hosts are fruit and wood trees, vegetables, cut flowers and weeds, which generate alterations in the hormonal balance producing symptoms such as philodias and virescence. Because its isolation in vitro has not been possible, the detection and characterization has been carried out, mainly, with molecular techniques. In addition, the use of New Generation Sequencing (NGS) has allowed to know the complete genome of some phytoplasmas, as well as the regions and genes that constitute it. In the present bibliographic review, the information generated from the molecular techniques and NGS sequencing is compiled, as well as the primers reported to identify some groups of phytoplasmas.