The nature of the interaction of Keggin-like aluminum oligomers with layered alpha-tin and alpha-zirconium phosphates (alpha-SnP and alpha-ZrP) has been studied by P-31 and Al-27 MAS-NMR, complemented with infrared and X-ray photoelectron spectroscopies. According to the type of aluminum solution used, monolayers and bilayers of the tridecamer ion [AlO4Al12(OH)(24)(H2O)(12)](7+) or dimeric polyoxocations, derived from this ion, are intercalated into the layered phosphates. The interaction of the phosphate layer with aluminum species causes a shift of the P-31 Signal toward high field. The Al-27 spectra show the typical resonance Lines corresponding to octahedral and tetrahedral aluminum, together with a third resonance at ca. 30 ppm assigned to pentacoordinated aluminum, that increases in pillared phosphates formed by calcination at 400 degrees C. From these results interlayer Al oxide pillars would be cross-linked to the phosphate layer through pentacoordinated Al. The interaction of aluminum with the phosphate layer is stronger in alpha-ZrP than in alpha-SnP.