Let M, be the algebra of all n x n complex matrices. If Phi:M-n-->M-n is a surjective mapping satisfying det(A+lambdaB)=det(phi(A)+lambdaphi(B)). A,B is an element of M-n, lambda is an element of C, then either phi is of the form phi(A)=MAN. A is an element of M-n, or phi is of the form phi(A)=MA(t)N, A is an element of M-n, where M, N is an element of M are nonsingular matrices with det(MN)=1. (C) 2002 Elsevier Science Inc. All rights reserved.