In a 0.4mol.L−1HOAc-NaOAc buffer solution, the catalytic hydrogen waves of the rhodium(III)-2-(3,5-dibromo-2-pyridylazo)-5-diethylaminophenol (3,5-Br2-PADAP) complexes were obtained by single-sweep polarography. The composition of the adsorptive complex was determined as Rh(III):3,5-Br2-PADAP = 1:2 by polarography. The electroanalytic properties of 3,5-Br2-PADAP are also discussed. The proposed oscillopolarographic method can be used for determining trace rhodium in the range of 4.8 × 10−10∼ 2.4×10−6mol.L−1without interference from other noble metal ions. The detection limit was 7.7×10−11mol.L−1.