Apple proliferation (AP) was first described in Italy in 1950, and occurs in many European pome fruit growing areas. In the last years new epidemics of the disease were reported in northern Italian regions. At least three phytoplasma subtypes have been reported in Europe, classified on the basis of the polymorphisms detected in the nitroreductase gene of 'Candidatus Phytoplasma Mali'. This work reports the results of the presence of AP in Lombardia and the characterization of the phytoplasma ribosomal protein subtypes associated with the disease in this region