Silver yttrium phosphates AgYP2O7 doped with Tb3+, Sm3+ and Dy3+ (x = 0, 1, 3 5, 10, 15, 20 mol%) were successfully prepared via solid state reaction. The similarity between all diffractograms of prepared phosphors confirm that they are a single pure phase. The Fourier Transform InfraRed (FTIR) analysis are in good agreement with structure type, the characteristic bands of P2O74−groups attributed to the symmetric and asymmetric stretching of P-O-P bridge, respectively are identified. The investigation on luminescence of Tb3+, Sm3+ and Dy3+ ions in this phase is reported. The cross-relaxation phenomenon widely known in phosphors based on Tb3+ is pointed out. A prediction of the nature of the occupied site by the rare earth ion was possible using the predominant intensity in both Sm3+ and Dy3+ ions.