With increasing frequency, clients are bringing malpractice claims against their patent attorneys. Malpractice and the risk of malpractice should be a matter of continuing concern to clients seeking patent services, individual patent attorneys, their firms and employers, the patent bar, and society as a whole, all of whom benefit from the fulfillment of the instrumentalist goals of the patent system. In this vein, one of the principal goals of tort law is to deter injurious conduct. For deterrence to occur, the actor must be able to anticipate that certain conduct may result in harm to others, so that such conduct may be avoided. A goal of this Article is to analyze the exposure of patent attorneys to malpractice claims and hence to promote deterrence of conduct that may result in economic injury to clients and others who may be affected. The Article first evaluates the theories upon which malpractice is based, principally professional negligence and breach of fiduciary duty. The respective elements of the professional negligence cause of action are analyzed with specific reference to the peculiarities of patent practice. The breach of fiduciary duty theory is similarly analyzed and compared. In the course of these analyses, the transferability to malpractice claims against patent attorneys of certain doctrines recognized with respect to other professions is considered. Common defenses to malpractice claims are then evaluated in the context of patent practice, in particular the functioning of statutes of limitations. Based on the preceding analyses, implications and conclusions are then offered.