The present study was conducted in October 2003 to investigate the factors related to psychological stress and the heavy burden of caregivers taking care of frail elderly persons in the northern part of the Onga district, Fukuoka Prefecture, Kyushu, Japan. A total of 40 caregivers were assessed using a self-administered questionnaire involving the Japanese version of the Zarit Caregiver Burden Interview (J-ZBI) and thus described their own caregiving situation. J-ZBI research had been done on a yearly basis for the previous 5 years and the results of each investigation regarding Center for Epidemiologic Studies Depression Scale (CES-D), and incidence of depression, ADL and dementia were compared prior to and after initiation of public long term care insurance for the elderly (LTCI). Compared to caregivers with a middle or light burden, heavily burdened caregivers were more likely to have a higher J-ZBI, and CES-D. Compared to caregivers with a light burden, heavily burdened caregivers were more likely to 1) be in poor condition, 2) complain of their economical situation, 3) spend a longer time with care talker. Compared to caregivers with a middle burden, heavily burdened caregivers more frequently used short-stay services (i.e., temporary nursing home assistance). J-ZBI and ADL were compared to before LTCI, and 4 years after LTCI had been started. Scores for both were lower after 4 years. Compared to before LTCI, day-care and day service were used less frequently 3 and 4 years after LTCI. After LTCI, caregivers showed a lower J-ZBI score, but the incidence of depression among caregivers was higher, compared to the general public. It is suggested that a government agency should be created to support not only the frail elderly but also their caregivers.