This paper evaluates the role of compromissory clauses as a source of ICJ jurisdiction. It analyses to what extent States have made use of the possibility, provided for in Art 36 (1) of the ICJ Statute, of providing for recourse to ICJ in international treaties. It presents a detailed analysis of compromissory clauses agreed since 1922 and of compromissory-clause-based cases brought before the ICJ. It argues that while the number of compromissory clauses remains extremely high, hardly any new such clauses have been agreed on in the last decades. While that may be deplored, many steps have already been taken, and the existing network of compromissory clauses, though uneven and incomplete, is much more dense than is often assumed. From the ICJ's perspective, compromissory clauses thus arguably are the most important basis of jurisdiction today. What is more, there are signs that States are beginning to realise that even the existing network permits them to seek binding decisions in a surprisingly broad range of disputes. Both factors taken together account for the continued relevance of compromissory clauses.