When a fabrication process is renewed, of practical importance is how to make the best use of layout resources so far accumulated for old fabrication processes. The present paper describes an automatic recycling system for layout data once used dedicatedly for functional cells of the standard-cell level, The main process of this system is i) to transform given layout data into a layout description format expressed in parameters associated with shapes, sizes, and locations of layout elements, and then ii) to resynthesize an optimal layout in accordance with a new set of design rules by means of a graph theoretic linear programming approach. A part of implementation results is also shown.