The electrochemical reduction of betamethasone valerate (BV) in a pharmaceutical formulation containing neomycin has been carried out in Britton–Robinson buffer (BRB) (0.04 mol L⁻¹) by differential-pulse polarography (DPP). BV exhibits a well-defined irreversible reduction peak at −1.03 V/ref. The influence of pH on the reduction of BV was studied in Britton–Robinson buffer (pH range 1.7–10). A method for the analysis of BV in BRB (0.04 mol L⁻¹), which allows quantification over the range 3.9×10^–6–1.1×10^–4 mol L^–1, was proposed and successfully applied to the determination of BV in tablets with mean recovery and relative standard deviation of 100.81% and 0.45%, respectively.