This paper examines bilateral double taxation treaties, with an emphasis on information exchange among tax authorities. A major objective is to understand which countries are more likely to sign a tax-relief treaty and when information-exchange clauses will be added to a treaty. A simple model with two asymmetric countries and repeated interactions among governments is used. The paper shows that no information exchange clause may be added to a tax treaty when there is a reciprocity requirement, when there is a high cost of negotiation, when there is a cost of providing information, or with one-way capital flows. It is also shown that an information clause increases the gains from a tax relief treaty, but may make it less sustainable.