In the past 50 years, the share of students enrolled in U.S. Catholic schools has declined from approximately 12% to 3%. In reaction, many urban Catholic schools have closed and subsequently reopened as public charter schools in order to receive governmental funding and to increase enrollment. As public schools, these Catholic- affiliated charter schools now face a complex set of legal and practical challenges. This article presents empirical research on Catholic-affiliated charter schools, and the legal issues facing them as well as the wider category of religiously-affiliated charter schools. The authors conclude by answering a number of questions that Catholic school leaders are likely to pose about this emerging trend in Catholic education.