The Ca and Mg content of flax and corn phosphatidyl inositol fractions has been determined. Procedures were devised to prepare various salt forms of phosphatidyl inositol. The divalent cations were exchanged for monovalent ions (Na or K) on chelating resin columns. With the Folch wash procedure the Na or K forms of phosphatidyl inositol were completely converted to the Ca form. The nature of the metal ion associated with the phosphatidyl inositol had a striking influence on the solubility properties of the lipid. The differences in mobility on silicic acid columns of the various salt forms were utilized to free the phosphatidyl inositol from nitrogenous contaminants.