NdCoO3 nanocrystals formed via glycine-nitrate combustion method followed by heat treatment has been systematically studied.Formation of NdCoO3 nanocrystals with minimal size of 7-10 nm from X-ray amorphous combustion products has been elucidated to be a very rapid process,occurring at the temperature of 550-600℃ for 5-30 min.The comparison of the minimum sizes of NdCoO3 crystallites obtained from the offered empirical relation dmin=lunit cell·N(where N is 7-12 and lunit cell is elementary cell parameter)and the data determined on the basis of X-ray diffraction(XRD)and transmission electron microscopy(TEM)showed good correlation.The existence of special nanoporous microstructure and spatial limita-tions prevent NdCoO3 particle growth.The kinetic equa-tion based on Avrami-Erofeev nucleation model was offered to be correlated well with experimental data of fractional conversion(α)versus isothermal time(τ).The apparent activation energy(Ea=(338±32)kJ)of for-mation of NdCoO3 nanocrystals from X-ray amorphous combustion products obtained in excess of oxidant fol-lowed by heat treatment at 550-600℃ was determined.