The aim of this work has been to determine the possibility of using lichens as polycyclic aromatic hydrocarbon (PAH) bioaccumulators for the evaluation of atmospheric pollution in the city of Rieti. A lichen sample collected in a remote unpolluted area was divided into 18 sub-samples. These were collocated in nine different stations in the city of Rieti and every 5 months the PAH concentrations were determined. Only phenanthrene, anthracene, fluoranthene, pyrene and chrysene were found at concentrations over the limit of quantification. In the meantime a continuous increase of their concentrations was observed.