RE(III) complexes of Naproxen(HNap) have been synthesized and characterized by elemental analyses, conductance measurements, solubilities, thermal analysis, infrared, proton magnetic resonance, and electronic spectral data. The elemental analyses reveal the presence of 1:3 (metal:ligand) stoichiometry and the IR spectra suggest the carboxylate group of HNap functions, as a bridging ligand to coordinate to RE(III) ions. The electronic spectra recorded in solid exhibit only slight shifts in visible regions, on which beta, delta and b1/2 of covalent parameters have been calculated. Formalin-induced rat paw edema and croton oil-induced rat ear edema inflammatory models were chosen to examine the antiinflammatory activity of Nd(III) complex, which ascertained enhanced antiinflammatory activity relative to the ligand.