For the purpose of developing a runoff model for polycyclic aromatic hydrocarbons (PAHs) in urban areas, this study focused on the contents and profiles of PAHs in road and roof dust. The result of cluster analysis of the profiles of PAHs in the size-fractionated dust showed that roof dust formed a different cluster from road dust irrespective of either the particle size or the roof structure. Factor analysis revealed that phenanthrene, indeno(1,2,3-cd)pyrene and benzo(ghi)perylene were important PAHs for distinguishing road dust from roof dust. The result of the factor analysis also suggested that the contribution of tires, pavements or asphalts to PAHs is greater in road dust than in roof dust and that the contribution of vehicle exhaust emission to PAHs is greater in roof dust than in road dust. A nonparametric test indicated that the contents of PAHs are higher in fine dust (smaller than 106μm) than in coarse dust (larger than 106μm).