The aqueous solubilities of acenaphthene, anthracene, and pyrene, three polycyclic aromatic hydrocarbons (PAHs), were measured at temperatures from 50 degrees C to 300 degrees C. A dynamic method was used in the production of saturated aqueous solution, and the amount of analyte was determined by gas chromatography-mass spectrometry. In solubility measurements below the melting point of the analyte, a flow-through saturation cell was applied, whereas for measurements above the melting point a new saturation cell was constructed and the experimental setup was optimized. Solubilities below the melting point correlated well with literature values. An exponential relationship between solubility and temperature was found for pyrene and anthracene. The mole fraction solubilities measured at 250 degrees C and 5 MPa were (1.25 +/- 0.097) x 10(-1) for acenaphthene, (4.97 +/- 0.89) X 10(-4) for anthracene, and (2.05 +/- 0.23) x 10-4 for pyrene. At 300 degrees C and 10 MPa, the values were (3.78 +/- 0.13) x 10(-3) for anthracene and (1.41 +/- 0.17) x 10(-3) for pyrene. Aqueous solubilities of pyrene, anthracene, and acenaphthene at such high temperatures have not been reported previously.