We fed herbicides to newly emerged workerApis melliferaL. in 60% sucrose syrup at concentrations of 0, 10, 100, and 1000 parts per million by weight.The following herbicides were relatively nontoxic to honey bees at all concentrations: 2,4-D, 2,4,5-T, silvex, 2,4-DB, dicamba, 2,3,6-TBA, chloramben, picloram, Ethrel®, 2-chloroethylphosphonic acid, EPTC, and dalapon. The following were extremely toxic at 100 and 1000 ppmw concentrations: paraquat, MAA, MSMA, DSMA, hexaflurate, and cacodylic acid. Two compounds, bromoxynil and endothall, were very toxic only at 1000 parts per million by weight (ppmw) concentration. Paraquat, MAA, and cacodylic acid were moderately toxic at 10 ppmw. No significant differences were noted in the toxicity of purified and commercially formulated herbicides.