In this paper we present a High Level Architecture (HLA) component model, particularly suitable for distributed multiscale simulations. We also present a preliminary implementation of HLA components and the CompoHLA environment that supports setting up and managing multiscale simulations built in the described model. We propose to integrate solutions from High Level Architecture (such as advanced time and data management) with possibilities given by component technologies (such as reusability and composability) and the Grid (such as joining geographically distributed communities of scientists). This approach will allow users working on multiscale applications to more easily exchange and join the simulations already created. The particular f...