NUCLEUS is a project developing the prototype of an integrated patient dossier. Facilities are being developed to allow customisation of the dossier and its contents for the various end-user categories. This is done by ensuring consistency, completeness and accuracy of patient data. Data protection and access control issues are addressed. The NUCLEUS project has produced 2 main types of results: three working systems, implementing an integrated patient dossier solution in the respective practical environments of 3 major European hospitals; integrated patient dossier services, integrated and delivered on a variety of platforms, including all operational and configuration and customisation facilities. Complete portability has been achieved by means of advanced configuration facilities.