Nursing assistants provide 90% of the functional and psychosocial care of older adults in nursing homes. Without knowledge of the normal physical changes of aging, it would be difficult to provide them with appropriate quality care. This quasi-experimental study aimed to test the effects of the Elderly Simulation Program on nursing assistants' knowledge about aging, attitudes toward older adults, and the motivation to care for older adults in nursing homes. The program has two parts: a 1-hour lecture about aging changes and a 1-hour simulation of the roles of an older adult, a caregiver, and a “rusher” (20 minutes for each role). A convenience sample of 83 full-time nursing assistants was recruited from nursing homes in Taiwan. The participants were assigned to an experimental (n = 43) or a control group (n = 40). The experimental group received the Elderly Simulation Program intervention, whereas the control group did not participate in any educational programs. Data were collected before the intervention and 4 wk after the program was completed. Results indicated that 4 wk after the intervention, the experimental group participants' knowledge about aging and attitudes toward older adults had significantly improved (all P < .001). The experimental group participants also had greater knowledge of aging than the control group at posttest (P < .001). It is recommended that the program be incorporated into the regular on-the-job continuing education of nursing assistants in long-term care facilities to enhance their knowledge about aging and their attitudes towards older adults.