The Routh frequency-domain reduction (approximation) method, coupled with powerful dominant pole-selection criteria, is introduced for the purpose of application to high-degree transfer functions of multiple-input multiple-output (MIMO) linear time-invariant systems to obtain corresponding adequate reduced-order models. The proposed method has been applied successfully to a 10th-order matrix transfer function of a two-input two-output time-invariant linear model of a practical power system.