Here is described a novel voltammetric method for boscalid. Boscalid is a broad-spectrum fungicide known to be electrochemically inactive. However, it forms complexes with cobalt(II) through its pyridine carboxamide group that allows its indirect determination by adsorptive cathodic stripping voltammetry after deposition at positive potentials. The catalytic character of the reduction peak at -1.2 V was established by the mechanistic studies. After optimization of the parameters, calibration relationships were obtained at nanomolar concentrations and the method was used to analyze tomato juice and tomato paste with satisfactory recoveries.