Before the mid-1980s, prenuptial agreements had tenuous legal standing in US state courts, which often refused to enforce them. In 1983 the National Conference of Commissioners on Uniform State Laws promulgated legislation called the Uniform Premarital Agreement Act (UPAA) that was designed to strengthen these agreements’ legal enforcement. Since then, 26 states and the District of Columbia have adopted the UPAA, rendering prenuptial contracts reliably enforceable in their courts. This paper uses data on UPAA adoption to investigate the effect that making prenuptial contracts legally enforceable has had on divorce rates. We find that rendering prenuptial agreements legally enforceable reduced divorce rates in America. We also present the first data on persons who use prenuptial agreements and the substance of those agreements in the United States.