Maintenance of TS in oil refinery is a very complex and demanding task. It is necessary to apply the most up-to-date concepts and techniques of maintenance in order to achieve optimal effect in maintenance and favorable economic effects. In the work the overview of maintenance works and cognitions about the maintenance including the newest trends of further development of maintenance are provided. The analysis of states of maintenance for the case Oil refinery in Sisak is provided, and overview of possibilities of quoted cognitions use about the maintenance in the concrete case. Determining and use of contemporary TS characteristics such as availability and reliability of TS, makes possible the bringing reasonable decisions for the management maintenance in practice and the production process in general. Data about interruptions throughout the period from 1999 to 2005 (6.5 years) have been gathered, processed and analyzed. On the basis of the obtained analysis results, the key cause that can be improved has been defined. Hereby the technical solution has been suggested for improving the present condition. And in the end economic effects resulting with the application of this solution have been taken into account. Review of necessary investments, costs prior and after improvements have been presented as well as realized savings and the period of returns of investment. On the basis of these results whole procedure has been generalized and has been made the algorithm of procedure for the promotion management TS in oil refinery, and there is possibility of its use in all industry.