The paper deals with the case law of the European Commission of Human Rights and of the European Court of Human Rights on the admissibility of individual applications on matters already submitted to other international bodies, under Art. 35, para. 2, letter b) ECHR. It examines the relevant procedural aspects and reviews how the Strasbourg bodies have interpreted the criteria set in this clause, which coordinates parallel international proceedings on the same matters, i.e. (i) the identity of parties, grounds and facts; (ii) the concluded or concurrent exam of the claim within other international mechanisms of protection of human rights open to individuals; and (iii) the equivalent character of these other proceedings in relation to the procedure before the European Court of Human Rights. It does so, particularly with respect to two recent decisions concerning cases where parallel proceedings on the same matter were brought, in the one case, by the same person before the Court as well as to the attention of the EU Commission, and, in the other case, by a legal person before the Court and by its shareholders before international investment arbitral tribunals. It highlights that the ‘reformed’ Court has normally followed the prior Commission’s case law but has also developed a more systematic and qualified approach to each admissibility criterion as well as to the overall objective of such coordination mechanism, in order both to avoid a plurality of international procedures on the same matter, on the one hand, and to afford the individual an international means of enforcement of her/his rights, on the other hand.