This paper presents the results of a trial implementation of IT-based systematization of control room operation. Most refining companies rely on reductions in the Distributed Control System (DCS) alarm frequency and the operation frequency to maintain safe and stable operation. Guidelines established by the Engineering, Equipment and Materials User's Association (EEMUA) recommend that 150 alarm events occur per day. However, in practice, this recommendation is extremely difficult to adhere to through the use of DCS and Model Predictive Controls and Alarm Monitoring Systems. IT-based systematization, consisting of an Intelligent Sequence Control System (ISCS) for automatic operation and an Advanced Monitoring System (AMS) for automatic monitoring, on the other hand, permits ready achievement of the recommendation target. Moreover, ISCS/AMS are very effective tools by which operators can easily systematize their knowhow. Over 30 ISCS/AMS systems have been implemented at petroleum /petrochemical refineries operated by Idemitsu Kosan in Japan since the year 2000. As a result of the application of ISCS/AMS systems, the following results have already been achieved: 1) Manual operation frequency has been reduced by 93% through the application of ISCS to shutdown operations. 2) Alarm frequency has been reduced by 88% through the application of ISCS to shutdown operations. 3) Operational knowledge has been partially systematized by ISCS/AMS. 4) ISCS/AMS have contributed to knowhow sharing and to the standardization of a high level of operational expertise.