Organic and inorganic extractions of citrus peels at 25 degrees C and ambient pressure were carried out to fractionate the components and to estimate solubility parameters of each extract. The obtained extraction yield was plotted against solubility parameter of each extraction solvent and the plots were fitted by the Gauss waveform. The peak of the waveform showed an experimentally estimated solubility parameter for each extract. The results were comparable with the calculation methods proposed by Fedors and Hansen within a deviation of 20%, and a method was proposed for estimating the solubility parameters from extraction results.