The failure envelopes of many soils are significantly nonlinear and the effect of this curvature on slope stability is examined. Charts, based on circular arc stability analyses, have been prepared and make possible the rapid assessment of the stability of slopes of simple geometry in uniform soils with curved failure envelopes. The effect on the factor of safety against stability failure of (i) the degree of curvature of the failure envelope of the soil, (ii) the magnitude of the pore pressure ratio within the slope, and (iii) the depth to a hard stratum has been investigated. Key words: depth factor, pore pressure, safety factor, shear strength, slope, stability.