Microstructural feature of the recrystallized Co-based (Co3Ti) and Ni-based (Ni3(Si,Ti) and Ni3Fe) ordered alloys with L12 structure was investigated by the electron back-scattering diffraction method with emphasis on grain boundary character distribution. For comparison, the grain boundary character distributions of the recrystallized Co–Ni, Ni–Fe and 70/30 brass disordered alloys, and also Cu, Ni and Al pure metals with A1 (face-centered cubic) structure, which have widely different stacking fault energies, were also determined. The frequency of Σ3 boundary for the Co-based alloys was higher than that for the Ni-based alloys, regardless of ordered L12 alloy or disordered face-centered cubic alloy, indicating that the frequency of Σ3 boundary was primarily dominated by stacking fault energy. Furthermore, the effect of ordering energy on microstructure and energy of the grain boundaries, including Σ3 boundary in the ordered L12 alloys was discussed. Effects of Stacking Fault Energy and Ordering Energy on Grain Boundary Character Distribution of Recrystallized L12-Type Ordered Alloys. Y.Kaneno, T.Takasugi: Materials Science and Engineering A, 2005, 393[1-2], 71-9