Conventionally, detection of phytoplasmas has been performed by PCR of the 16S rRNA gene, followed by either RFLP or DNA sequencing to determine the phytoplasma 16Sr group. This chapter demonstrates the technique of terminal restriction fragment length polymorphism (T-RFLP), a fingerprinting technique which combines both detection and identification in a single method, with the added benefit of inbuilt controls which removes the risk of false negative results and in addition highlights potential false positive results.