Science Gateways are frameworks (or toolsets) which incorporate applications, data and tools to enable running applications on Grid infrastructures. They also provide services to support, upload, search, manage and download (or share) applications and data. The gateways are integrated via portals or sets of applications. Gateways enable user communities associated with a common discipline to use compute and data resources through a common graphical user interface in an easy and intuitive way. As a result, users can focus on their applications instead of learning and managing the complex underlying infrastructure.