Ternary oxides of the type AgLnIIITiO4 (with Ln = La, Nd, Sm, Eu, Gd, Dy, Y) have been prepared and their unit cell parameters determined by X-ray powder diffractometry. They are related to the K 2NiF4 structural type, with the AgI and Ln III cations distributed in an ordered way on the K-sub lattice. The infrared spectra of these materials were recorded and discussed on the basis of their structural peculiarities and by comparison with those of related oxides. They show a close relationship with the parent NaLnIIITiO4 materials.