Bojan Milisavljević, Bojana Čučković
The paper analyzes an issue of fundamental significance for international law – the procedure for the identification of custom in public international law. Since customary law may be qualified as a sui generis source of international law, instruments and procedures for proving customs are of major importance. Particular attention is given to the role of custom in modern international law. The first part of the paper outlines the work of the International Law Commission relating to formation and evidence of customary law, including its identification. The second part of the article analyzes the jurisprudence of the International Court of Justice concerning the process of formation of customary law, instruments through which it is evidenced, as well as the procedures for evidencing it. Particularly noteworthy is the necessity to introduce objectified rules for detecting customs and to determine the scope of these rules, both internationally – for a number of actors, as well as internally – in the legal systems of States.