In this Study, the solubility of a common polyaromatic hydrocarbon, pyrene, was investigated in various solvent systems containing p-xylene, octane, iso-octane and/or octanol over a temperature range from 293 to 318 K. The collected experimental data for the solubility of pyrene in pure solvents follow the Van't Hoff relationship with high accuracy. The experimental solubility data for six binary solvent systems were used to predict the interaction parameters for different models; Wilson, modified Wilson, nearly ideal binary solvent (NIBS)/Redlich-Kister and UNIQUAC. The interaction parameters for these models were expressed as a second order polynomial function in temperature. These obtained interaction parameters for the different used activity coefficient models were tested on more complex systems for the solubility of pyrene in ternary and quaternary solvent mixtures composed of different ratios of p-xylene, octane, iso-octane and/or octanol at different temperatures (ranging from 293 to 318 K). Using extended forms of the NIBS/Redlich-Kister model resulted in improvements in the prediction of pyrene solubility. Functional group contribution models (UNIFAC, UNIFAC-SG, SUPERFAC, SUPERFAC-SG, Dortmund UNIFAC and Dortmund UNIFAC-SG) were tested against all the pure, binary, ternary and quaternary solvent systems. Detailed comparison between all of these models is presented. (c) 2007 Elsevier B.V. All rights reserved.