The main scope of HellaGrid is the provision of High Performance Computing and High Throughput Computing services to Greek academic and research community. So, the resources of the grid infrastructure are used by Greek researches and researches involved at various European projects. The last years, an more and more increased number of researches coming from various scientific fields (high energy physics, computational chemistry, biomedicine, informatics, meteorology, seismology, etc.) uses the HellasGrid infrastructure in order to cover their needs for computational and storage resources.