We investigated the lattice parameters and luminescent properties of Pr-doped perovskite-type lithium ion conductors with the nominal composition, A(0.6-3x/2)Pr(x)Li(0.3)Ti(0.5)Ta(0.5)O(3) (A =Ca and Sr, 0 <= x <= 0.05). Ca0.6Li0.3Ti0.5Ta0.5O3: Pr showed the intense red emission corresponding to the f-f transition of Pr3+ (D-1(2)-> H-3(4)) on the ultraviolet photo excitation with the energy corresponding to the band gap of host. In contrast, Sr0.6Li0.3Ti0.5Ta0.5O3: Pr exhibited blue-green and red emission on the excitation with blue light corresponding to the f-f transition of pr(3+) (H-3(4)-> P-3(2))- It was found that these differences in luminescent properties primarily originate from the occupation site of Pr in these perovskite-type oxides. (C) 2007 Elsevier B.V. All rights reserved.