Optimum conditions were found for direct current and differential pulse voltammetric determination of anticancer drug Flutamide and its main metabolite 4-nitro-3-trifluoromethylaniline on a hanging mercury drop minielectrode in mixed Britton–Robinson buffer (pH 12.0)–methanol (9:1) or 0.01MNaOH–methanol (9:1) media with limit of quantitation ca. 10–7mol l–1. It was proved that the newly developed method is applicable for the determination of Flutamide in pharmaceutical formulations and for the determination of both Flutamide and 4-nitro-3-trifluoromethylaniline in urine either directly with limit of quantitation ca. 10–5mol l–1or after solid phase extraction with limit of quantitation in the 10–7mol l–1concentration range. The sufficient peak potential difference of the two substances suggests the possibility of the analysis of their mixtures.