A new approach to the study of the main patterns and kinetics of hydrothermal synthesis of transition metals nanocrystalline oxides is proposed. It is based upon applying Calvet calorimetry as the main kinetic method together with X-ray diffraction (XRD), CSD measurements and electron microscopy (SEM, TEM) of final products. Examples of applying the proposed technique are given as well as kinetic analysis and modeling of hydrothermal synthesis of nanocrystalline TiO₂, ZrO₂ and HfO₂ from the corresponding amorphous hydroxide precursors.