The European framework surrounding clinical trials on medicinal products for human use is going to change as demonstrated by the large debate at European institutional level. One of the major challenges is to overcome the lack of harmonisation of clinical trial procedures among countries. This aspect is gaining more and more importance, considering the increasing number of multicentre and multinational studies. In this work, the actual European rules governing the Clinical Trial Application have been analysed throughout the different steps including (...) the registration of the trial in the European database; the preparation of documents to be submitted and their contents; the preparation of documents related to the information and consent process; the submission to competent bodies. Specific issues related to paediatric research and trials involving non EU/EEA countries have been addressed as well. Results reveal that the European legislation offers a well defined set of European rules covering different aspects of a Clinical Trial Application. However, these are not suitable to meet the challenges from multicentre and multinational clinical studies. A stronger set of rules, such as is available in a composite European Regulation has been adopted and is expected to harmonise practices and enable sponsors to carry out well conducted trials. But will the new regulation overcome the existing criticisms of Directive 2001/20/EC? (shrink)