RE-40885 (5-(methylamino)-2-phenyl-4-3-(trifluoromethyl phenyl)-3(2H)-furanone), a newly developed herbicide with soil and foliar activity, was evaluated for weed control in peanuts (Arachis hypogea L.). RE-40885 applied to the soil or foliage provided excellent Florida beggarweed (Desmodium tortuosum (Sw.) DC.) and prickly sida (Sida spinosa L.) control at rates of 0.56 to 1.12 kg ai/ha. Sequential applications of RE-40885 were needed to achieve > 90% sicklepod (Cassia obtusifolia L.) control. Texas panicum (Panicum texanum Buckl.) was not adequately controlled by any of the RE-40885 treatments evaluated. Peanuts were not injured by RE-40885 at any of the evaluated rates or application times. The combination of RE-40885 and 2,4-DB applied early postemergence improved sicklepod control 8 weeks after planting when compared to either RE-40885 or 2,4-DB applied alone. The combination of R E-40885 and alachlor applied at peanut emergence improved morningglory (Ipomoea spp.) control 8 weeks after planting and increased peanut yield when compared to either applied alone. All treatments containing RE-40885 resulted in peanut yields that were significantly better than nontreated weedy control plots.