BalticGrid-II on the Way to Interoperability Olgerts Belmanis1, Ake Edlund2, Robert Palak3, Ilmars Slaidins1 1Riga Technical University 2Royal Institute of Technology in Stockholm 3Poznan Supercomputing and Networking Center Abstract Fast and non-coordinated development of regional ICT based e-Infrastructures creates challenges of interoperability. Now new projects and initiatives have started to make e-Infrastructures standards based, user friendly and interoperable. In this paper the BalticGrid II project is presented and the project efforts in the promotion of standards and to maintain interoperability of grid systems. The Baltic region is a relatively small geographic area where three major middlewares’ user communities overlap. There are gLite, ARC and Unicore. gLite is the dominant middleware used in the region due to the official status of it in the BalticGrid and BalticGrid-II projects. The key services of Grid are Job Submission, Information Services, Storage Management, Accounting, Job Monitoring, Database Access and Virtual Organization Management. BalticGrid-II project is promoted interoperation of the gLite-based infrastructure with UNICORE and ARC. Activity SA1 “Grid Operation” include the separate task to develop interoperation with UNICORE and ARC resources within the region. There are two solutions: interoperability and interoperation. Interoperability between these middlewares can be achieved organizationally and technically. Now BalticGrid-II use gLite and therefore is interoperable with EGEE. To provide progress MoU with KnowARC project and Unicore has been signed. The first important solution is Migrating Desktop. Developed by PSCN within Joint Research activity Migrating Desktop is advanced user friendly interface which provide interoperation between several production grids, based on various middlewares (e.g. gLite,,Unicore, ARC, i2g, GT4). Project partners are actively participating in e-IRG, OGF, EUGridPMA and EU Technical Groups of Grid and implementing accepted recommendations.