Although grid computing middlewares are in research use since many years, they lack of particular security features for biomedical applications. The analysis of the common Globus middleware reveals several security-related shortcomings. As a result, extended security measures for HealthGrids have been identified. They include tools for auditing, tracking, fine grained access control for structured documents, trust and trust delegation. The German MediGRID project is facing this with an “Enhanced Security” package intending to bridge the gap between current legal, data protection as well as data security requirements and the available grid technology.