The concentrations of 27 polycyclic aromatic hydrocarbons (PAHs), including six carcinogenic PAHs, were measured in leaves of Quercus ilex L. and surrounding soils in order to evaluate their suitability as biomonitors of PAH air contamination. Healthy and mature leaves and surface soils (0-5 cm) were collected at five urban sites and one control site in May and September 2001 and January and May 2002. The PAHs were extracted by sonication and quantified by GC-MS. Both leaves and sous showed PAH accumulations at the urban sites and spatial trends of PAH concentrations among the sites, although no correspondence was highlighted between the spatial trends among leaves and soil PAH concentrations. The temporal variations in PAH concentrations were wide for the leaves with the highest values in January, whilst for the soils they were narrow. The 3-ring PAHs were the most abundant in the leaves whilst the 6+7-ring PAHs were the most abundant in the soils. The proportions of the carcinogenic PAHs to the total were on average about 15% and 25% in the leaves and soils, respectively.