We present a coupled wave analysis of nonlinear magnetostatic surface waves in ferromagnetic slabs which have double periodically corrugated surfaces. Most relevant are the effects close to the Bragg condition. The nonlinearity of the system shifts downwards and widens the stop bands, however the relative spatial phase difference between the two surface corrugations has significant influence on the widths of stop bands and under certain conditions weakens the nonlinear effects of the system. ©1995 American Institute of Physics.