A summary of the situation for detecting and naming phytoplasmas associated with different diseases in the last 30 years is presented in this chapter. In the last decades, a great amount of research has been devoted to classifying and differentiating these prokaryotes by molecular and bioinformatic tools applied to the analysis of specific phytoplasma genes. The availability of a robust classification system has greatly facilitated phytoplasma identification, leading to increased knowledge of their associated plant diseases worldwide. Scientific knowledge on phytoplasma biology still needs to be improved to allow better and more focused management solutions with minimal impact on the environment to mitigate the severity of these diseases in both agricultural and natural environments, also contributing to reduce the loss of biodiversity.