A possible origin of the characteristic susceptibility (magnetization) peaks in the mixed orthotitanate Pr 1 - x Nd x TiO 3 (0=<x=<1), which has been found for 0.5<x<1, is proposed based on the results of DC and AC magnetization measurements. Considering the identical results to those in La 1 - x Sm x TiO 3 and Ce 1 - x Nd x TiO 3 , it is assumed that the phenomenon is brought about by the formation of a cluster-glass. In small x regions, the following phenomena are observed. Magnetization-field (M-H) curves show inflection at H<1.2x10 6 A/m (~15 000 Oe), plausibly due to a spin-flop of Pr 3 + moments. Only at 2 K, the systems exhibit discontinuous jumps of magnetization at some applied fields. From the experiment on a powder sample, this behavior is attributed to rotation of magnetic domains induced by the applied field.