It will be shown that the equivalence classes of C*-algebra extensions of C(X) relative to a II^,-factor and Hom(A'(Jf), R) are isomor-phic. This provides a proof for the result of Brown, Douglas _and Fillmore [5] on the isomorphism between the former group and Hom(A/^-Y), R). Let % be a separable infinite dimensional Hubert space, £(%) the algebra of all bounded linear operators on %, %(%) the ideal of compact operators, and &(%) the quotient algebra £(%)/%(%). In [3], [4], [5], ExtX was defined as the set of equivalence classes of C*-algebra extensions, 0^%(%)^&-^C(*)^0 for X a compact metric space and C(X) the algebra of continuous complex-valued functions on X, or equivalently as the unitary equivalence classes of unital *-monomorphism t: C(X)-> &(%). It was shown that Ext X is an abelian group and that it is a generalized homology theory. One of the basic facts about Calkin algebra used in the theory of C*-algebra extensions is the Weyl-von Neumann Theorem, which was generalized to semifinite factors by L. Zsido [10]. P. A. Fillmore has extended part of this theory to semifinite factors [6]. That is, let M be a II«,-factor in % with a dimension function d, %(M) the ideal generated by the finite projections, and &(M) the quotient algebra M/%(M). Extw X was defined as the set of unitary equivalence classes of unital *-monomorphisms t: C(X)-» &(M). An extension t is trivial if t can be factored through M, that is, if there exists a unital *-monomorphism a of C (X) into M such that t = ir ■ a, where it is the natural homomorphism of M onto M/%(M). The sum of t, and r2 is the extension defined as follows: choose isometries Vx and V2 in M such that VXV* + V2Vl = l,and let (T, + t2)(/) = *(Vx)Tx(f)?r(Vt) + *(K2)t2(/MK2*) for all/in C(X). The equivalence class of t, + t2 is independent of choice of isometries in the definition, trivial extensions form the identity element, and