Solubility values of propylthiouracil dissolved in four neat solvents of N,N-dimethylformamide (DMF), N-methyl-2-pyrrolidone (NMP), dimethylsulfoxide (DMSO), and ethylene glycol (EG) and aqueous cosolvent solutions of DMF, NMP, EG, and DMSO from 293.15 to 333.15 K were determined. The determination process was carried out using the saturation shake-flask method at 101.1 kPa. At the identical temperature and cosolvent composition of DMF, NMP, EG, or DMSO, the solubility of propylthiouracil in mole fraction was maximum in DMSO (DMF) (1) + water (2) systems, and minimum in EG (1) + water (2) systems. Through the vant Hoff-Jouyban-Acree, Jouyban-Acree, and Apelblat-Jouyban-Acree models, the solubility of propylthiouracil was correlated very well, acquiring root-mean-square deviation values that are smaller than 9.75 x 10(-4) and relative average deviation values that are smaller than 3.01%.