Eighteen new complexes of lanthanide perchlorates and nitrates with 3-methyl 1-phenyl pyrazol-5-one (MPP) have been synthesized and characterized. The complexes have the general compositions [Ln(MPP)6] (ClO4)2 and [Ln(MPP)2 (NO3)3] where Ln=La, Pr, Nd, Sm, Gd, Tb, Dy, Ho and Y. Conductance studies in nitrobenzene and acetonitrile indicate 1∶3 electrolytic behaviour of perchlorate complexes and non-electrolytic behaviour of nitrate complexes. All the complexes show normal magnetic behaviour. The IR spectra show the monodenticity of the organic ligand and the presence of ionic perchlorate and coordinated nitrate. The electronic spectra indicate 6-coordination for perchlorate complexes and 9-coordination for nitrate complexes. Thermal studies (TG, DTG and DTA) indicate that the perchlorate complexes are thermally less stable than the nitrate complexes.