The structural mechanism which accommodates nonstoichiometry in V 2O 3 was investigated by transmission electron microscopy. The existence of distinct diffuse scattering was observed as the boundary of the homogeneity range was approached. The analysis of the diffuse scattering indicates the formation of one-dimensional microdomains in the c direction having a structure similar to VO 2. Orientation relations between V 2O 3 and V 3O 5 (which is formed from V 2O 3 by heat treatment in an oxidizing atmosphere) show that V 3O 5 is formed by redistribution of vanadium ions among the octahedral interstitial sites of common close-packed sublattice consisting of oxygen ions. Possible relations between the present observations and physical properties in nonstoichiometric V 2O 3+ x are discussed.