An accurate and sensitive novel method was designat ed chemically for the determination of atenolol in pharmaceutical drugs. The complex forma tion between copper(II) and atenolol was studied both in aqueous and methanolic media. Compl ex formation depends on reaction conditions at different metal-to-ligand molar ratio s. The mononuclear violet complex cation Cu(Atenolol) 4 +2 contains two ligands in an anionic bidentate form (through the hydroxyl oxygen and amino nitrogen) and two in a neutral form bound monodentately with an distorted octahedral geometry. The new analytical method base d on measuring absorbance in UV-visible at λ max 350nm. Optimum pH and divalent copper ion conce ntration were estimated. Linearity (40-250), detection limits 07*10 -7 M. were determined. The complex is identified with UV-visible and IR spectra. The molar ratio also investigated a nd found 1:4(Cu:Atn).