This paper presents a case study fulfilled at the maintenance sector of a metallurgical company. The research problem addressed was the satisfactions level of customers of the maintenance. The objective was to quantify the performance of preventive and corrective maintenance, mechanical and electrical, in relation to customer satisfaction. To achieve this aim, we conducted an applied research, quantitative, developed by a case study. With the knowledge of some theoretical models of performance measurement, we adopted the Key Performance Indicators – KPI – as the most suitable method for measuring proposal. With this, it developed questionnaires to assess the satisfaction of the performance of maintenance. After the data collection, spreadsheets were created to quantify the answers to the questionnaires. The results of this study present the responses to the seven requirements that assess the satisfaction of preventive maintenance and six requirements that assess customer satisfaction of corrective maintenance services. It is concluded that the measurement of maintenance performance, by measuring customer satisfaction becomes important criterion for planning and ascertainment of industry guidelines for maintenance of the company.