In sunflowers, the incorporation of resistance to the fungus Plasmopara halstedii generally involves the use of methodologies that are not very accessible due to their high cost. The use of simple techniques would permit easier access to cultivars resistant to this parasite. This paper describes an approach combining two techniques for an early screening test for downy mildew resistance in sunflower. The whole-seedling immersion technique was applied to immature germinated seeds of different sunflower cultivars in a suspension of Plasmopara halstedii zoosporangia. This methodology did not produce any negative or modifying effect on resistance to the mildew, it was capable of producing similar disease reactions when the genotypes under evaluation were naturally infected by this pathogen in other experiments. It is concluded that this new and innovating technique allows resistant sunflower genotypes to be identified at very low cost in breeding programs.