Centaurium erythraea Rafn. (sin. Erythraea centaurium Pers.; Gentianaceae), known also as red centaury (or European centaury), is an annual or biennial medicinal and aromatic plant, native of Europe and North Africa, wild in Italy. European centaury acts beneficially on the liver and kidneys, purifies the blood; it has been long used for the cure of intermittent fever. This plant contains a bitter principle, erytrhocentaurin, which constitutes an excellent tonic widely used in liquor industry. Because it can not be easily cultivated is harvested as wild plant in July, when just breaking into flower. In order to better understand agronomical aspects of this species, some experimental fields were set up at an Agronomic Research Centre located in Trentino Region (Northern Italy). In July 2008, a phytoplasma-like disease was observed. After first symptoms observation in May, an increasing percentage of symptomatic plants were found in the following months, at the blooming stage. Yellows symptoms were present in the leaves and, in some cases, the plants showed reduction of leaf size and stunting. At blooming, the plants showed abortion of buds, flower virescence, rosetting and malformation. In order to verify phytoplasma presence and to determine their identity, samples from symptomatic and asymptomatic plants were collected and tested by direct PCR with primers P1/P7 followed by nested PCR with primers F1/B6 and 16SF2/R2 (Duduk et al., 2004). RFLP analyses performed with TruI and HhaI enzymes, allowed the identification in the symptomatic plants of phytoplasmas belonging to group 16SrI-B (‘Candidatus phytoplasma asteris’). This is the fist report of a phytoplasma natural infection in European centaury. In fact, a phytoplasma from the clover proliferation group (16SrVI) was reported in 2001 in Centaurea solstitialis a weed plant belonging to the family Asteraceae (Faggioli et al., 2003). To now only phytoplasmas belonging to subgroup 16SrIII-B (clover yellow edge) have been found naturally infecting species of the Gentianaceae family (such as Gentiana sp.) in 1995 and 1997 in Japan and Thailand respectively (Okuda et al., 1997).