Three different farming systems for Ontario, Canada were compared from technical and economic standpoints. The conventional system farms relied upon government-prescribed rates of synthetic herbicides for weed management. Reduced-input system farms used crop rotations and tillage systems as partial substitutes for synthetic herbicide inputs. Organic system farms proscribed the use of synthetic herbicide treatments entirely, relying instead on crop choices and sequences, tillage methods, animal manure composting, and other management tools for weed control. All farm types had similar natural resource endowments, but conventional farms were the most specialized and operated the largest land base, while organic farms were the most diversified and smallest.