Four fungicides, i.e. Curzate~M, mancozeb (Dithane M-45), chlorothalonil (Daconil) and metalaxyl (Ridornil) in the WP formulations at various rates and times of application were evaluated for their effectiveness in the control of Chinese cabbage downy mildew caused by Peronospora parasitica under epiphytotic conditions with reinforced artificial inoculation in the field. Ridomil 25 WP applied three times at one week interval at a rate of 2.0 kg/ha, beginning 28 days after transplanting was found to be the best agent among the 4 fungicides tested for the control of downy mildew of Chinese cabbage. Ridomil treatment resulted in a 65% increase in yield of marketable cabbage while affording complete protection, by preventing the causal organism of the disease from developing, throughout the entire crop growth season. The data obtained from this study are highly significant at P = 0.01 level. At 125 ppm and higher levels of Ridomil application, both conidial spore germination and growth of germ tubes of P. parasitica were completely inhibited.