Core European eInfrastructure for large-scale eScience research consists of the backbone GÉANT network; distributed storage & computing infrastructure - European Grid Initiative (EGI); and the PRACE initiative providing tier-0 High Performance Computing (HPC) infrastructure. South-East European eInfrastructure initiatives aim for equal participation of the less-resourced countries of the region in the European trends. SEEREN initiative established a regional network and the SEE-GRID initiative the regional Grid, with majority of countries now equal partners in GÉANT and EGI. BSI project established the GÉANT link to the Caucasus, active until mid-2010. However, HPC involvement of the region is limited. Only few HPC installations are available, not open to cross-border research; while the less-resourced countries have no mechanism established for interfacing to the pan-European HPC initiatives.HP-SEE focuses on a number of strategic actions. First, it will link the existing and upcoming HPC facilities in the region in a common infrastructure, and provide operational solutions for it. As a complementary action, the project will establish and maintain the GÉANT link for Caucasus. Second, it will open this HPC infrastructure to a wide range of new user communities, including those of less-resourced countries, fostering collaboration and providing advanced capabilities to researchers, with an emphasis on strategic groups in computational physics, chemistry and life sciences. Finally, it will ensure establishment of national HPC initiatives, and act as a SEE bridge for PRACE. In this context, HP-SEE will aim to attract the local political & financial support for long-term sustainable eInfrastructure.HP-SEE aspires to contribute to the stabilisation and development of South-East Europe, by overcoming fragmentation in Europe and stimulating eInfrastructure development and adoption by new virtual research communities, thus enabling collaborative high-quality research across a spectrum of scientific fields.