In a general sense, St. Thomas Aquinas predicted the paralysis and chaos of the financial and economic systems in America and Europe which occurred in 2008, when he predicted that in a society where unjust exchanges dominate, eventually all exchanges will cease. St. Thomas also points out that although human law cannot prohibit all injustice, society cannot escape the consequences of transgressing the divine law which leaves “nothing unpunished.” Thus, at least part of the explanation for that crisis whose effects remain with us today lies in continuous violations of natural justice by our economic system. Neither one product nor market is completely responsible for these injustices. Yet, there is one area of economic justice, understood in light of Catholic doctrine, which has been largely ignored in the late 20th and 21st centuries–Just Price Doctrine. The search for causes and solutions to the current crisis must include a re-acquaintance with this element of Catholic Truth. This chapter examines the history of the philosophical/legal concept of Just Price from its origins in Greek philosophy and Roman law through its adoption by Christianity and considers its application to our contemporary economic system. The chapter concludes that a reinvigoration of this moral doctrine in our economic law is necessary to a reinvigoration of our economies.