The research presented in this paper concerns the development of a methodology for monitoring and continuous performance improvement. The proposed approach is derived from the classical Deming cycle adapted to a real industrial environment. The approach consists of four phases: Monitor, Analysis, Action and Review (MAAR); these phases are summarized in a single information panel that allows to improve the monitoring process. This paper presents a discussion of the real case study application of the methodology in area manufacturing of ANSALDO STS S.p.A. The case study discussed here shows the application of basic principles, management tools and techniques towards performance improvement in a manufacturing plant. The innovative issues of the MAAR approach developed regard: the possibility to apply the methodology to wide fields of enterprises (as maintenance, quality management, design, financial, etc.) and the real-manufacturing orientation. The results show the real benefits obtained by the implementation of the proposed methodology.