The single-phase NiFe2O4 and CoFe2O4 ferrites were synthesized by four methods: the high-frequency plasma-chemical synthesis („plasma”), sol-gel self-propagating combustion method („combust.”), and co-precipitation technology, combined with the hydrothermal synthesis („hydrotherm.”) or spray-drying („spray”). The specific surface area (SSA), crystallite size, and magnetic properties of the synthesized products have been determined. The synthesized ferrites are nanocrystalline single-phase materials with crystallite size of 5-40 nm. The SSA of nanoparticles synthesized in plasma is 28-30 m2/g, the particle size distribution is in the range 10-100 nm, with some individual particles up to 200 nm. The SSA of the ferrites obtained by the self-combustion and hydrothermal synthesis is 40±3 and 60±5 m2/g, respectively. The SSA of the samples obtained by the spray-drying method is 80-90 m2/g and the calculated particle size is 13-15 nm. In this process, pellets up to 10 μm are obtained. After synthesis, CoFe2O4 are characterized by the saturation magnetization Ms of 75 emu/g („plasma”), 53 emu/g („combust.”) and 57 emu/g („hydrotherm.”). The Ms of NiFe2O4 is 44, 29 and 30 emu/g, respectively. The products obtained by the spray-drying method are partially X-ray amorphous and show magnetic properties only after heating above 450 °C. These nanopowders were used in sintering studies.