This paper describes a new approach to robot path planning : the transition cost matrix based approach. By defining the concept of transition cost matrix and the 2-ary operator on the transition cost matrix, the optimum paths are generated from the operations on the matrix, thus the optimum paths between all points in the environment can be achieved via limited matrix operations to attain the aim of constructing the optimum path set at the preprocessing stage. The paper ends with the application of the proposed approach for mobile robots’mission planning.