Shared decision-making programs, or patient decision aids, have been developed for difficult decisions in which patients need to consider benefits versus risks.Decision aids currently used in practice in Ottawa, Ontario, Canada.Published studies of patients faced with decisions about hormone therapy, prenatal testing, lung cancer treatments, and anticoagulation for atrial fibrillation; administrative data on distribution of decision aids; and a survey mailed to pulmonologists and surgeons.Although most patients considering health care options arrive for counseling with strong predispositions toward a particular option, some are uncertain about their choice and express the need for information, clarification of values, and advice about their options. Decision aids prepare patients for decision making by increasing their knowledge about expected outcomes and personal values. The aids are used in our local centers, and more than 6000 kits have been distributed in Canada, the United States, Europe, and Australia. They primarily affect the decisions of patients who are undecided at baseline and sometimes reduce the proportion of patients who choose more intensive options.The Ottawa patient decision aids assist patient decision making, particularly among those who are undecided.