Markets are affected by strong competition in terms of continuous innovation of products and processes, high customer satisfaction and low cost of production. In order to achieve these strategic results it is recommended, or necessary, to rectify lack of organisation. For instance, the increasing costs due to material handling, force factories to check the facility layout and, when necessary, to improve it. The evaluation of a prospective improvement requires a large effort and a wellestablished skill. The study and the optimisation of plant layout is a strategic activity. This paper represents the last step of a research program on the automatic design of plant layout.The aim is to support the design activity of plant layout by means of an integrated approach, taking into account many criteria, both quantitative and qualitative. In particular, this paper presents a global approach, based on material flow and activity relationships. It is carried out using new software, called LRP (layout and re-layout program), introduced by the authors. A real application in a factory, specialising in the production of electronic devices, is presented.