Ten herbicides were evaluated for poison-hemlock control in established alfalfa in Utah. Hexazinone, metribuzin, and terbacil controlled poison-hemlock 90% or more but diuron and pronamide did not. Either glyphosate or 2,4-D applied in May at 1.1 kg ae ha-1 controlled poison-hemlock 97 to 98% compared to 60 to 75% with 2,4-DB at that rate. Dicamba and bromoxynil did not control poison-hemlock.