This paper summarizes briefly the existing methods for the analysis and presents simple considerations of liquefaction potential due to earthquakes and flow failures of slopes made of sandy soil for eight case histories in order to indicate the accuracy and usefulness of the simple considerations in routine engineering practice. Simple consideration of liquefaction potential of slopes in sandy soil during earthquakes is based on calculation of factor of safety of slope stability before liquefaction using pseudo-static limit equilibrium method, the shear to axial stress ratio defined using the equivalent sliding block method and the empirical charts used for assessment of liquefaction potential of level ground. Simple consideration of flow failure of sandy slopes is based on Bernoulli’s equation for conservation of energy along a flow line of incompressible fluid.