The aim of present study was to measure and correlate the solubility of poorly water-soluble flavonoid diosmin in water, ethanol, isopropyl alcohol (IPA), polyethylene glycol-400 (PEG-400) and beta-cyclodextrin (beta-CD) aqueous solution (0.02 mol.L-1). The solubility of diosmin was measured using the shake flask method from (298.15 to 333.15) K at atmospheric pressure. The experimental solubilities of diosmin were regressed by the modified Apelblat model with a relative deviation in the range of 0.048% to 5.940%. The correlation coefficients were observed in the range of 0.9957 to 0.9995. The solubility of diosmin was found to be increased with temperature in all sample matrices investigated. The mole fraction solubility of diosmin was found to be higher in beta-CD aqueous solution and PEG-400 as compared to water, ethanol and IPA. Based on solubility data of present study, diosmin was considered as practically insoluble in water, insoluble in ethanol & IPA and soluble in PEG-400 and beta-CD aqueous solution. (C) 2014 The Chemical Industry and Engineering Society of China, and Chemical Industry Press. All rights reserved.