Following the recent report on the criteria for standardization of pH measurements in aqueous organic solvent mixtures [Pure Appi. Chem. 57, 865–876 (1985)1, the present report concerns the re-examination of reference value standards (pHRVS) and primary standards (pHS) determined prior to 1985, the aggregation of new standards freshly determined in the light of IUPAC rules and procedures, and the compilation of recommended data. The PHRVS data (the RVS material is the 0.05 m potassium hydrogenphthalate buffer) now available cover the following solvents and/or their mixtures with water: methanol, ethanol, 2-propanol, l, 4-dioxane, acetonitrile, dimethylsulphoxide, and heavy water (D20); the various PHS now available cover methanol, ethanol, dimethylsulphoxide and D20.