The synthesis of L-α-glyceryl-(2-phthalimidoethyl)phosphonic acid and of L-α-glyceryl-(2-aminoethyl)phosphonate, the latter a phosphonic acid analogue of L-α-glycerylphosphorylethanolamine and a possible intermediate in phosphonolipid metabolism, is described. The compounds were obtained by condensing D-acetone glycerol with (2-phthalimidoethyl)metaphosphonate in boiling benzene, and freeing the condensation product, viz. acetone L-α-glyceryl-(2-phthalimidoethyl)phosphonic acid, of its acetone group to obtain L-α-glyceryl-(2-phthalimidoethyl)phosphonic acid, or of its phthaloyl and acetone groups to give L-α-glyceryl-(2-aminoethyl)phosphonate.A procedure for the preparation of (2-phthalimidoethyl)metaphosphonate is reported.