The necessary conditions for maximum power transfer to the outputs of a multiport are discussed. The condition Z = Z 0 *is sufficient. A solution to this problem is not generally unique, because the matrix Z must satisfy the matrix equation Z(Z 0 + Z 0 *)-1E 0 = - Z 0 (Z 0 + Z 0 *)-1E 0 + E 0 . When the power transfer is maximum, only the total power of the equivalent sources is equally divided between the "passive" multiport and the ports.