The problem of the nonlinear filamentation of lower‐hybrid waves in a two‐ion species magnetized plasma has been investigated. The dominant nonlinear effect comes from the existence of two ion species if the concentration of second ion species is larger than (me/mi)s−1(with 1<s<3/2). The nonlinear Schro¨dinger equation and the modified nonlinear Schro¨dinger equation describing the nonlinear self‐distortion of the propagation cones of lower‐hybrid waves due to the interaction with low‐frequency ion‐ion hybrid perturbations are derived for the case of fast phase variation. In the case of slow phase variation the nonlinear self‐distortion of the propagation cones of lower‐hybrid waves is described by the modified Korteweg–deVries equation when the ion‐ion wave is at the Buschbaum frequency. The nonlinear equation which governs the asymptotic state of filamentation admits an exact solution, describing solitons, envelope solitons, or cusped envelope solitons for the electric field. These solitons represent the nonlinear stage of the evolution of the purely growing mode which appears in the parametric analysis.