The reactions of Al(NO3)3 with N-(phosphonomethyl)iminodiacetic acid and with N-nitrilo- tris(methylene-phosphonic acid) in aqueous solution at various pH values afforded crystalline materials, which represent new Al(III)-organophosphate species. The isolated crystalline materials were characterized by elemental analysis, spectroscopic techniques (FTIR, NMR) and X-ray crystallography. The new species contain aluminum ions in an octahedral environment and reflect chemical reactivity of that metal ion with phosphonatecontaining substrates in biologically relevant fluids.