Grapevine downy mildew (Plasmopara viticola) is a major disease causing widespread destruction in vineyards throughout the world. It was introduced into France in 1878, in the wake of the Phylloxera epidemic, and was discovered by Planchon in vineyards in Coutras (Bordeaux region). This chapter describes the resistance of this pathogen to some fungicides in France, including phenylamides, mitochondrial inhibitors (quinone outside inhibitors and quinone inside inhibitors), cell wall inhibitors (carboxylic acid amide fungicides), cymoxanil, and multi-site and miscellaneous fungicides; and presents several anti-resistance measures.