This article sets out some basic guidelines on how to make mandatory mortgage disclosure effective. It is largely based on the experience of the US, which has had extensive disclosure rules for several decades. Such guidelines should be useful to other countries that now face the need for mandatory disclosure, or will in the future. Market-oriented economists opposed to all types of government regulation usually make an exception for markets characterized by extreme information asymmetry. It is well understood that markets don’t work well when one party to transactions has vastly more information than the other. Because mandatory disclosure is designed to make markets work better, it is viewed much more favorably than price controls, which distort the allocation of credit; or contract controls, which reduce the options available to consumers. The home mortgage market is a textbook case of information asymmetry. One party is in the market continuously, the other very infrequently — sometimes only once or twice in a lifetime. Furthermore, transactions can be extremely complex. There may be multiple instruments from which to select, multiple options with each instrument, complex pricing arrangements, and frequent price changes. For the borrower, there may be a lot to learn and very little time in which to learn it. To be sure, complexity varies greatly from one country to another — the US has the most complexity by far. Many other countries are moving in the same direction, however, propelled by the same forces that have operated in the US: the development of secondary markets and increasing competition. In the European Community, integration is intensifying these pressures. Countries moving rapidly toward greater complexity in their home loan markets, and therefore toward greater information asymmetry, will need to consider mandatory disclosure. Hopefully, the many mistakes made in the US can be avoided. Poorly designed disclosures can do more harm than good.