A series of rare earth oxide mixed manganese nodules (perovskite type mixed oxides) have been prepared by coprecipitation method followed by calcination at 900 degrees C and characterized by different techniques. The effect of rare earth ions on the surface, textural and catalytic activity for the oxidation of CO, and decomposition of H2O2 have been discussed. The activity for CO oxidation followed an order : Pr greater than or equal to La > Nd > Yb > Dy > Tb > Sm > Tm > Gd > Eu > Ce.