A simple and sensitive polarographic method is described for the determination of prenalterol hydrochloride through treatment with nitrous acid. The different experimental parameters affecting the derivatization process, as well as the polarographic analysis were studied. The derivatization product was found to be reducible at the dropping mercury electrode over the whole pH range in Britton-Robinson buffers. At pH 5, a well defined diffusion-controlled cathodic wave was produced. The limiting current vs. the concentration plot was linear over the range 0.015-0.15 mM in the direct current mode, with a minimum detectability of 0.8 microM. The proposed method was applied successfully to the determination of prenalterol hydrochloride either in the pure form or in its dosage forms.