The operation of vessels is more and more accurately monitored and collected information allows for rationalization of decisions related to maintenance of technical assets. The article defines a universal maintenance performance indicator (UMPI) using methods of numerical taxonomy. It was reviewed the purposes of use of performance indicators (KPI – Key Performance Indicators) and suggested to apply a universal indicator, connecting different groups of information and allowing ranking of technical objects according to multicriterial evaluation of maintenance performance. There is an example of application of universal indicator, which was calculated for a hundred of technical objects recognized by the vessel’s shipowner as critical in the system of operation. The results allowed to rank objects from the best to the worst maintained according to multicriterial evaluation. It was defined the direction for further research on a universal indicator of maintenance performance