Healthcare data and medical information need to be seamlessly accessible and available at all times to the various healthcare stakeholders. Inability to share, integrate and access critical healthcare information is a challenge for the healthcare IT. Moreover, semantic interoperability of health-related heterogeneous data sources is a challenging issue and HealthGrids are expected to address this challenge in a systematic manner. This paper proposes a new architecture: ASIDS (Architecture for Semantic Integration of Data Sources), that could be a potential candidate for solving the challenge of semantic interoperability of geographically distributed heterogeneous data sources. ASIDS has three main components that are loosely coupled (through interfaces) in a distributed manner. This architecture sets the basis for future research in terms of implementing a HealthGrid application in real environments.