The solubility of pioglitazone HCl (99 data points) in binary mixtures of polyethylen glycols (PEGs) 200, 400 or 600 + water at three different temperatures which ranged from 298.2 K to 308.2 K were reported. Three different cosolvency models; yalkowsky, Jouyban-Acree and combined version of the Jouyban-Acree model with van't Hoff approach, have been used for correlating the reported data, and the correlation OMRDs are 65.2%, 18.0% and 17.8% respectively. Also, a previously trained version of the Jouyban-Acree model has been used for predicting these 99 reported data points which the prediction OMRD is 23.4%. (C) 2014 Elsevier B.V. All rights reserved.