This paper presents the results from an inventory of validation approaches and methodologies which have been used in selected health telematics projects. The inventory was performed in the VATAM Validation of Telematic Applications in Medicine project, HC1115HC. The purpose of the inventory was to analyse the methodologies and their application assumptions in order to identify possibilities for harmonization and consolidation. The inventory was performed using five validation dimensions: IT-development; quality; user; technology assessment and marketing. The inventory results show that possibilities exist to synthesise methodologies and to provide practical guidance and support for projects that are developing health telematics applications. All stakeholders in health telematics projects, i.e. users, health care decision-makers, developers, suppliers and IT-industries, can benefit from practical validation guidelines and support for validation when guidelines are represented in a usable, easy to access and informative way.