Abstract: The invention relates to an MgB2 based powder for the production of superconductors, having high reactivity which can be sintered at visibly lower temperatures and which can be compacted in large high density samples having a high superconductive transition temperature and a high critical current. The aim of the invention is achieved by virtue of the fact that the powder is a mechanical alloy powder, whose particles have an average size of d<250 &mgr;m and a substructure consisting of nanocrystalline grains whereby the dimensions thereof are <100 &mgr;m. The inventive powder can also contain additional chemical elements in the crystal grating of the MgB2-power particles.