Field trials were carriedoutduring winter seasons of 1981–82 and 1982–83 to assess the efficacy of the herbicide chlortoluron and hand weeding in controlling weeds in opium poppy at the Rajasthan College of Agriculture, Udaipur. Application of Chlortoluron at 1.5 kg/ha resulted in high yield of opium latex and seed and low weed count and weed dry matter yield at harvest, compared with the effect of hand weedings after 20, 40 and 60 days.