Solubility parameters are introduced for the first time to investigate the solubility problem of liquid crystals. Using Fedors method that is used for polymers and organic solvent gives solubility parameters of liquid crystals in the range of 8.0 (cal/cm(3))(1/2) to 11.0 (cal/cm(3))(1/2) . Polar liquid crystal compounds have large solubility parameters compared with nonpolar ones. Moreover, an aromatic ring, which is frequently encountered in liquid crystal compounds, increases the solubility parameter value. Since these parameters can be used to calculate the activity coefficient in regular solution theory, we attempted to investigate the solubility of solids and gases for two types of liquid crystal solvents, namely a polar nematic liquid crystal solvent and a nonpolar one. We found that the solvent dependence could be explained by the solubility parameter difference between a solute and a nematic liquid crystal solvent.