Experiments were conducted to determine the efficacy, absorption, andtranslocation of nicosulfuron, rimsulfuron, and nicosulfuron + rimsulfuronon barnyardgrass, green foxtail, longspine sandbur, and large crabgrass. Inthe greenhouse, nicosulfuron, rimsulfuron, and nicosulfuron + rimsulfuronwere applied at 0.0625, 0.125, 0.25, 0.5, 0.75, 1, and 2 times their labelrates of 35, 13, and 26 + 13 g ai ha−1, respectively, on 5- to10-cm plants. Three weeks after treatment (WAT), barnyardgrass was the mostsusceptible species to all three herbicides, and large crabgrass was theleast susceptible. The nicosulfuron, rimsulfuron, or nicosulfuron +rimsulfuron rates causing 50% visible injury (GR50) forbarnyardgrass were 10.9, 4.8, and 6 + 3 g ai ha−1, respectively.Similarly, the GR50 for large crabgrass were 25.6, 9.9, and 14.3+ 7.2 g ai ha−1, respectively, 3 WAT. Absorption of nicosulfuron,rimsulfuron, and nicosulfuron + rimsulfuron was greater in barnyardgrassthan in large crabgrass. Absorption of nicosulfuron + rimsulfuron inbarnyardgrass and large crabgrass was 74% and 57%, respectively, 7 d aftertreatment (DAT). In addition, translocation of nicosulfuron, rimsulfuron,and nicosulfuron + rimsulfuron out of the treated leaf was 14, 12, and 14%higher, respectively, in barnyardgrass than in large crabgrass. Thedifferential response of these weed species to nicosulfuron, rimsulfuron,and nicosulfuron + rimsulfuron might be due to differences in herbicideabsorption and translocation.