Stands of leafy spurge (Euphorbia esula L.) were reduced over 90 per cent by 20 combinations of crops, cultivation, and herbicides. Three of the best crop rotations in two 4-year trials were: (1) a short season of intensive cultivation, a mid-August seeding of alfalfa, a crop of alfalfa, spring wheat sprayed with ½ lb/A of 2,4-dichlorophenoxyacetic acid (2,4-D) (an ester formulation was always used) three postharvest cultivations, corn sprayed with $13 lb/A 2,4-D; (2) a short season of intensive cultivation, a mid-August seeding of bromegrass sprayed with 1 lb/A 2,4-D in early June and mid-August during the second and third years, and a crop of corn the fourth year; (3) spring oats sprayed with $13 lb of 2,4-D ester and three postharvest cultivations, three spring cultivations a close-drilled crop of sudangrass and fall cultivation, spring wheat sprayed with $12 lb/A of 2,4-D ester and three fall cultivations, a crop of corn sprayed. The best use of nonselective herbicides in four 2-year trials was spring application of 4 to 6 lb/A of 2,3,6-(trichlorobenzoic acid (2,3,6-TBA), plow 10 days later, followed by a corn crop and a spring oats crop, both treated with 2,4-D and 4 to 6 lb/A of 2,3,6-TBA applied after oats harvest, and the field plowed 10 days later. Reinfestation by seedlings was prevented by an annual spring application of $13 to $12 lb/A of 2,4-D per acre.