The ozonation of three to five ring condensed polycyclic aromatic hydrocarbons (PAH) was studied in synthetic oil/water-emulsions by batch experiments. PAH can be oxidized selectively in the presence of high concentrations of dodecane as an aliphatic solvent. No oxidation of dodecane, as a representative of mineral oil, could be observed during all experiments - even at pH around 11. At acid to neutral pH high oxidation rates of the PAH were achieved due to a direct reaction with ozone. In the investigated range of 20 to 40°C no influence of temperature on the ozonation of benzo(k)fluoranthene could be found. During competitive ozonation of five PAH, the reactions are completed in the sequence of acenaphthene, pyrene and finally benzo(e)pyrene, benzo(k)fluoranthene and phenanthrene almost at the same time.