Abstract: As the Catholic Church struggles with the aftermath of the clergy sexual abuse crisis, some have explored the possibility of an ecclesiastical code of professional conduct. Lawyers' long and storied history with professional codes offers a cautionary tale to those exploring an ecclesiastical code of ethics. As priests to our secular religion of law, lawyers are called forth and mandated by a competent authority to function in a defined role, the specifics of which are reflected, in part, in lawyer codes. As lawyers moved from Canons of Ethics (1908) to a Code of Professional Responsibility (1969) to Rules of Professional Conduct (1983, revised in 2002), the provisions grew more directive. They are designed to assist in the regulation of the profession, which results in provisions that are crafted to define baselines of conduct that justify punishment if the actor falls below that base. The natural tendency of codes is to move toward specificity, with a corresponding danger of losing sight of the fundamental values that drive the code. An ecclesiastical code will face similar pressures. In addition, lessons from the legal profession suggest other challenges and opportunities of an ecclesiastical code. First, who gets to craft the first draft, quite apart from the complex question of adoption, will reveal much about the goals and likely success of a code. Second, such a code must acknowledge and confront the inherent limitations of all rules: identifying the optimum level of discretion and understanding the role of fact-finding within a code. Third, drafters must understand - as they inevitably do - the necessity of ethical awareness as a precondition for the effectiveness of any code. Fourth, as a code articulates the contours of the role-differentiated behavior of the professional, it must be sufficiently flexible to reflect the challenges of role-differentiated behavior. Finally, and perhaps most importantly, a code of conduct by its nature focuses on the function of the individual professional and can be an awkward, and often ineffective, vehicle for addressing the need for changes in the institutional structures within which the professional functions. Against these challenges sits a huge and incredibly important benefit - education.