We have developed a system with a flexible RFID (Radio Frequency IDentification) antenna mat to assist caregivers in a group home. In Japan, a group home is a type of home-based care service for elderly persons who suffer from dementia. The caregivers working in the group home must always pay attention to such persons. Since the level of dependency of each elderly person is different, the caregivers must check whether the person requires support or not. However, the checking demands extra efforts on part of the caregivers in addition to the support tasks. To simplify this task, we introduce a system consisting of RFID antenna sheet sensors and RFID tags embedded in inner shoes or slippers of the elderly persons. The system can assist the caregivers to monitor the activities of the persons with dementia by specifying whether the person passed through the sheet on the corridor. It not only helps the caregivers to understand such persons by reviewing their activities but also keeps them informed about the person’s ongoing activities.