Zafirlukast is a competitive and selective leukotriene receptor antagonist, which is indicated for the prophylaxis and treatment of mild to moderate persistent and chronic asthma. A new, simple, and sensitive adsorptive stripping voltammetric method was developed for the determination of zafirlukast in pharmaceutical formulations. The analysis was performed in pH 8.0 of borate buffer. At a well-defined cathodic peak currents were measured with a hanging mercury drop electrode at -1232 mV with 20 s of accumulation time vs. Ag/AgCl reference electrode. The influence of several variables including supporting electrolyte, pH, accumulation potential, accumulation time, pulse amplitude, and scan rate on the adsorptive stripping response of zafirlukast were evaluated. The linear calibration range was 38.00-412.00 ng mL(-1). The detection and quantification limits were 15.00 ng mL(-1) and 38.00 ng mL(-1), respectively. The method was validated by evaluating validation parameters and applied for the determination of zafirlukast in its pharmaceutical formulations. The results obtained from developed method were compared with a spectrophotometric method reported in the literature and no significant difference was found statistically.