Two experiments were performed in Londrina, PR, Brazil to evaluate the efficacy of fungicides on the control of soybean (Glycine max) powdery mildew (Microsphaera diffusa). One application of the different commercial products was made on soybean cv. EMBRAPA 48 growth stage R4. The best fungicides to control powdery mildew were tebuconazole-1 and tebuconazole-2, carbendazin-1 and carbendazin-2. Test 1 - tebuconazole-2 (150 g a.i. / ha), prochloraz + propiconazole (225 + 62.5), propiconazole + carbendazin-1 (50 + 175), and tebuconazole-1 + propiconazole (75 + 62.5); Test 2 - carbendazin-1 (250), carbendazin-2 (250), and tebuconazole-2 (100).