International regimes are social institutions in issue-areas which consist of agreed upon principles, norms, rules, decision-making procedures and programmatic activities. They are based on formal international legal agreements, but they can also consist of informal agreements or social conventions. The IRD-project selected a set of “hard law”-regimes for coding. Each of them has been based on one or various legally binding international agreements.In a number of cases, “soft-law”-regulations complemented “hard-law”-provisions of regimes. Before the coding of a regime could begin, a number of conceptual issues had to be clarified. These issues center around one basic question: What is a case? The signing of an international legal document (whether it has been legally binding or not) can be considered as the date that marks the beginning of a regime’s existence. But regimes can also expire. The topic of regime demise has been ignored by regime analysts.1 The research community paid far more attention to exploring the creation or further evolution of international regimes. Only such regimes were included in the database which were in operation until the end of the twentieth century. The year 1998 represents the end point of the life-cycle explored for each regime. The coding has been carried out from 1999 onward.