Promusicae, a Spanish collecting society holding exploitation rights to musical and audiovisual recordings, was seeking an order before a Spanish court to require Telefónica to disclose the identities and addresses of certain of its customers. Promusicae believed these customers were infringing Promusicae’s rights through KaZaA, a file exchange programme. Telefónica refused on the grounds that, under Spanish law, the communication of personal data was authorised only in criminal investigations or on public security/national defence grounds. The Spanish court referred a question to the European Court of Justice (ECJ) to ask whether, in order to ensure effective protection of copyright, EU Member States were required to lay down obligations to communicate personal data in the context of civil proceedings. Having reviewed the obligations contained in a series of Community Directives on electronic commerce, harmonisation of copyright and the enforcement of intellectual property rights, the ECJ concluded that there was no such obligation under Community law.