An optimum design technique of a stiffened plate structure which acheives minimum compliance is developed. The stiffened plate structure is discretized into the finite shell elements, and the minimum compliance problem of the stiffner height subjected to the volume is formulated. Introducing the design sensitivity analysis, an optimum distribution of stiffner height of the rectangular waffle plate supported at the corners which has stiffners of the latticework type is determined by the sequential quadratic programming technique.