A limit equilibrium method for progressive failure analysis of slopes is proposed based on a technique of non-vertical slices . The local factors of safety are calculated by defining variable factor of safety instead of conventional single value factor of safety along a shear surface. Reasonable simplifying assumptions about the inter-slice forces and the line of thrust are made to render the problem statically determinate. Strain softening, though in an approximate manner, is considered in the solution procedure. The analysis of a field case history indicates that the proposed method realistically represent the behavior of progressive failure of an actual slope. Another case study revealed that in certain conditions a reasonable solution can be obtained using non -vertical slice approach, but the vertical slice analysis does not work well in obtaining reliable results . The proposed method, which can also handle vertical slice division, enables the user to choose more appropriate results either from vertical or from non-vertical slice analyses.