This experiment aims to determine the efficacy of an herbicide with active ingridient 2.4 D dimethylamine 870 g / l to control common weeds in the cultivation of lowland rice plants. The experiment was conducted in Tomo, Kabupaten Sumedang, West Java on June until October 2019. The experimental design used was a randomized block design with 4 replications and 7 treatments. The treatment consisted of a dose of herbicide with an active ingridient 2.4 D dimethylamine 870 g / l which was a dose of 1.5; 2; 2.5; 3; 3,5 l/ha, manual weeding and control treatment (without weed control). The results showed that herbicide with active ingridient 2,4 D dimethylamine 870 g / l starting at a dose of 1.5 to 3.5 l / ha can control weeds Ludiwigia octovalvis, Sphenochloa zeylainica, Fimbristylis miliacea, Cyperus iria and overall weeds up to 6 MSA without causing any effects poisoning in lowland rice cultivation.