Structural studies have been performed on precipitation hardening discovered in Ll₂-ordered Ni₃(Al, Cr) containing 0.2 and 0.5 ㏖% of carbon in terms of transmission electron microscopy(TEM). By aging at temperatures around 1073 K after solution treatment at 1423 K, fine polyhedral precipitates appear firstly on the dislocations and then in the matrix. The selected area electron diffraction (SAED) studies revealed that these particles are a M_(23)C_6 type carbide which has the cube-cube orientation relationship with the matrix lattice. Weak-beam electron microscopy observations of deformation induced dislocations suggested that the dislocations bypass the carbide particles during deformation.