We consider the propagation of a crack in inhomogeneous media. To determine the crack’s trajectory, we use the variational principle and the optical-mechanical analogy; as a result, the trajectory is an extremal of the functional of energy dissipation while fracture. We derive a nonlinear differential equation which describes the trajectory of a crack in an inhomogeneous medium under arbitrary predetermined loads and study the regions of stability of this equation for the particular types of media. We demonstrate that there are such zones in the medium where the crack can hardly reach.