Activity is a basic human need expressed in work and leisure pursuits. Unfortunately, people with dementia have a low rate of activity participation because of associated physical and cognitive constraints. Recently, the American Therapeutic Recreation Association (ATRA) held a consensus meeting to address this issue and formulate practice guidelines for recreation therapy in the care of people with dementia. The consensus document presents an evidence-based intervention theory that draws on the science of two disciplines: nursing and recreation therapy. This article reports on the ATRA guidelines and illustrates their applicability in a case study of a resident with severe aggression associated with dementia.