Epitaxial MnSi1.7was grown locally on both (111) and (001)Si. The orientation relationships were found to be [11¯0]MnSi1.7//[111]Si, (220)MnSi1.7//(22¯0)Si and [001]MnSi1.7//[001]Si, (100)MnSi1.7//(400)Si for epitaxy grown on (111) and (001)Si samples, respectively. Three variants of epitaxy, required by the symmetry consideration, were also observed to form on (111)Si. Interfacial dislocations were identified to be of edge type with (1)/(6) ⟨112⟩ and 1/2 ⟨110⟩ Burgers vectors for epitaxial MnSi1.7grown on (111) and (001)Si, respectively. The presence of different forms of MnSi1.7is suggested in view of the important difference in details of diffraction patterns of MnSi1.7along the [001] direction. The growth of epitaxial MnSi1.7on silicon has filled the ‘‘gap’’ of the growth of stable phases of silicides of the fourth period transition elements in the periodic table epitaxially on silicon.