The emergence of the human immunodeficiency virus (HIV) as a serious public health threat has rekindled long dormant debate about individual physicians' duty to treat potentially contagious patients. Because of the widely accepted common-law tenet of the "no duty [to treat] rule," previous work on a duty to treat focused on historical reviews, medical society position statements, and the ethical arguments upon which the statements are based. The passage of the Americans with Disabilities Act has rendered these discussions moot by creating, through federal civil rights mechanisms, a legal duty to treat patients with HIV, enforceable under considerable penalties. The paper also concludes that there has been inadequate attention paid to similar civil rights concerns of infected physicians.