Earth slopes are generally designed in an environment characterized by numerous uncertainties, stemming from limited sampling efforts on soil strata with variable soil properties, amplified further by the discrepancy between in situ and laboratory measured soil strengths. Additional uncertainties are also introduced from various simplifying assumptions and idealizations that are necessary for a practical mathematical analysis of stability.The uncertainties involved in the short-term stability of soil slopes have been evaluated from an extensive literature survey. A procedure for developing design of earth slopes based on a permissible risk is formulated whereby experience, published research results, experimental test data and judgement can be consistently incorporated in the evaluation of uncertainties and reliability of a given design. An example of slope design is presented to illustrate the proposed risk-based design method.