A solution to the steel slab design problem provides huge savings in the steel industry. Generally, this is a combinatorial optimization problem and it is NP-complete. In this paper a dynamic programming model is presented in order to provide an elegant optimal solution for one variation of the problem. The heuristic used in the model is presented as well. The computational results obtained on real-life instances of the problem are reported and compared with the results obtained on the same instances with the legacy optimization model, and they show a considerable improvement.