Maintenance and its costs have a significant role in today's businesses. The modern maintenance system provides a useful tool for monitoring company's maintenance costs and material management. With a system the maintenance will be more reliable and workable. As a target company is liquid gas terminal FGG Finngas GmbH branch in Finland. The company had no pre-existing maintenance system so the need for a system was great. The aim of this work was to plan the maintenance system which meets the needs of the company. This work deals with the company operations, maintenance as a concept, data systems of maintenance and maintenance systems of different suppliers. Interviews of maintenance personnel and the maintenance strategy of the company enabled to define the features of the system. Inquiries to the suppliers were sent and basis of those inquiries few system were selected for a closer inspection. The work resulted in the maintenance system which is suitable for this company. Implementation of system is intended to start in autumn 2013. With the new system, the company's maintenance should be more reliable and the system enables allocating resources to the right places.