This paper describes how a common database can play an important role in reaching cost-effective improvements of maintenance performance. The definition and overall design of a common database is presented and illustrated by a case. The main result presented is that it is possible to access a more correct view of the situation in the production by data integration and thereby have a better base for taking decisions in maintenance. The common database supports the development of applications for e.g. monitoring the performance of a production process, for deciding the most cost-effective maintenance policy or for simulating possible maintenance solutions.