This study aims to determine the efficacy of sodium bispiribak 400 g/l herbicide against weeds in lowland rice cultivation with direct seed planting systems. The experiment was carried out for 5 months, from July 2020 to November 2020. The experimental design used was a randomized block design with 4 replications and 6 treatments. The treatments consisted of a of the sodium bispiribak 400 g/l herbicide at a dose of 11.25 g/ha; 15 g/ha; 18.75 g/ha; 22.5 g/ha; manual and control weeding (no weed control). The test results showed that sodium bispiribak 400 g/l herbicide from a dose of 11.25 g/ha to 22.5 g/ha could control Ludwigia octovalis, Marsilea crenata, Monochoria vaginalis, Fimbristylis miliacea, Cyperus iria, and other weeds. Sodium bispiribak 400 g/l Herbicide starting at a dose of 11.25 g/ha to 22.5 g/ha does not cause poisoning in rice plants. Herbicide treatment Sodium bispiribak 400 g/l from a dose of 11.25 g/ha to 22.5 g/ha gave rice yields that were not different from manual weeding.