Evidence-based medicine is currently a fashionable term. The evidence that warfarin is safe, effective, and cost beneficial in preventing stroke in AF, DVT treatment, and DVT prophylaxis is mounting. However, the evidence that warfarin remains underutilized in these conditions is also mounting. There is new evidence that supports conservative management of overanticoagulation without bleeding. The amount of time, if any, that patients are off warfarin for various procedures is being reduced. Warfarin interactions with other agents continue to be reported so that practitioners can avoid or treat them. Even the contraindication of warfarin in pregnancy is being reexamined. Those with expertise in anticoagulation therapy have an imperative to inform colleagues about the evidence in favor of warfarin.