Atomic force microscopy (AFM) was employed to analyse ultrafine MnZn ferrite powders, obtained by precipitation from metal sulphates and sodium hydroxide at 110 and 190 degrees C, under hydrothermal conditions. Particle sizes measured on AFM images taken at the surfaces of pressed samples ranged from 10 to 40 nm, as a function of synthesis temperature, and were in good agreement with measurements made using X-ray diffraction and the Brunnauer-Emmett-Teller (BET) technique. Direct observation a Iso showed that the particles were monodispersed and approximately spherical in shape, meeting the requirements for the production of high density sintered components. Using a straightforward sample-preparation technique, AFM proved to be a powerful tool for direct analysis of ceramic powder particles on the nanometre scale.