In order to reduce the level of dithiocarbamate fungicide mancozeb residues in blackcurrants, two different ozone treatment procedures were evaluated. The first one entailed washing the plant material with an aqueous solution of ozone. This ozone enriched water solution allowed for a 59% reduction of mancozeb residues, compared with the initial concentration. The latter method was based on the utilization of ozone in a gaseous phase combined with a drying process. In that procedure, samples of blackcurrant fruit were exposed to a 19 ppm ozone concentration, and then the blackcurrants were dried. The utilization of ozone in a gaseous phase permitted a 38% reduction of mancozeb residues, in comparison with the initial concentration. As a result of the combination of both processes; ozonation and drying, a 58% reduction of mancozeb residues was achieved.