An additional term has been incorporated into the adiabatic mode parabolic equation (AMPE) to account for mode coupling. The coupled mode parabolic equation (CMPE) involves the solution of coupled horizontal wave equations for the mode coefficients. The numerical solution may be obtained efficiently using the splitting method. The first step is identical to the numerical solution of the AMPE. The second step involves Crank-Nicolson integration of the coupling term. The accuracy of the CMPE has been confirmed for two-dimensional problems involving coupling due to sloping bottoms and volume heterogeneities. The CMPE has been applied to three-dimensional problems involving both mode coupling and azimuthal coupling. It is practical to apply the CMPE to large-scale problems and possibly even global-scale problems at low frequencies. [Work supported by ONR.] [sup a)]A. T. Abawi is presently at AETC, Inc., 10975 Torreyana Rd. 300, San Diego, CA 92121.