The solubility of pioglitazone hydrochloride (form I) in methanol, ethanol, 1-propanol, acetic acid, and N,N-dimethylacetamide has been measured between 278.15 and 323.15 K at atmospheric pressure. The solubility of pioglitazone hydrochloride (form I) increases with increasing temperature and the order is N,N-dimethylacetamide > methanol > acetic acid > ethanol >1-propanol. The experimental data were correlated well by the Apelblat equation.