A concise algorithm is proposed in this paper for the calculation of the factor of safety of a slope using the Morgenstern-Price method. Based on force and moment equilibrium considerations, two expressions are derived for the factor of safety F-s and the scaling factor lambda, respectively, both in relatively simple forms. With this algorithm and assumed initial values of F-s and lambda, the solutions for F-s and lambda are found to converge within a few iterations. Compared to other procedures, the present algorithm possesses the advantages of simplicity and high efficiency in application. It is rather straightforward to implement this algorithm into a computer program.