The investigations were carried out at Dharwar and Gadag during 1968-69 to study the efficacy of herbicides applied either in the. crop rowan in the entire plot on seed cotton yield. Substituted-urea compounds like Diuron and Cotoron applied in the crop row at 0.625 Kg./ha controlled weeds effictively and produced more seed cotton yield. Weed index (W. I.) values were low in plot where diuron and cotoron were applied in the crop rows, suggessting that reduction in seed cotton yield due to weed competition is considerably less. Tire application of herbicides for cotton in the crop row seems to be better than in the entire plot.