This report is based upon an extensive compilation of the literature covering aniline points and critical solution temperatures in aniline of pure hydrocarbons. The best values of both properties have been selected for those hydrocarbons for which sufficient data are available. As an aid to this selection, a relationship between aniline point and molecular structure has been developed. In making the correlation two types of compounds gave trouble. Aromatic compounds have exceedingly low aniline points, which cannot be measured directly, and certain solid hydrocarbons give discordant results because the aniline point is below the melting point. These types of hydrocarbons have been studied by dissolving them in other compounds and obtaining blending values. The use of aniline points in the analysis of hydrocarbon mixtures is discussed briefly.