The present study investigated the solubilization of valdecoxib in aqueous solution using poly(ethylene glycol) 4000, poly(ethylene glycol) 6000, poly(ethylene glycol) 8000, and poly(ethylene glycol) 10 000 at (298.15, 303.15, and 308.15) K. The analysis of valdecoxib is carried out by UV spectral measurements at lambda(max) = 202 mn. The aqueous solubility of valdecoxib could be enhanced by the addition of an increasing mass fraction of all of the poly(ethylene glycols) tested as well as by increasing the temperature of the dissolution media. The molecular weight of the poly(ethylene glycols) tested played an important role in valdecoxib solubilization in the aqueous medium. Among the poly(ethylene glycols) studied, poly(ethylene glycol) 4000 exhibited a higher solubilization potential than the others. Calculated Gibbs free energy values were all negative for all of the poly(ethylene glycol) + water mixtures at (298.15, 303.15, and 308.15) K, indicating the spontaneous nature of valdecoxib solubilization. In the case of poly(ethylene glycol) 4000 + water mixtures, the Delta(tr)Gdegrees values decreased to a greater extent than those for the other carriers {poly(ethylene glycol) 6000, poly(ethylene glycol) 8000, and poly(ethylene glycol) 10 000) + water mixtures}, indicating that the reaction conditions were more favorable in poly(ethylene glycol) 4000 + water mixtures than in other carrier + water mixtures.