Problems and Objective: The National Health Insurance (NHI) and social welfare agencies have implemented the Elderly Health Examination Program (EHEP) for years. No study has ever attempted to evaluate whether this program is cost-effective. The purpose of this study is first to understand the prevalence and incidence rates of hypertension and further to estimate cost and effectiveness of the EHEP, focusing on hypertension screening. Data and Methods: The data sources were: 1) hypertension and clinical information derived from the 1996 and 1997 EHEP which was used to generate prevalence and incidence rates of hypertension; and 2) claim data of the NHI that included treatment costs of stroke patients (inpatients and outpatients). Hypothetical models were used to evaluate the cost-effectiveness of the hypertension screening program in various conditions. Sensitivity analysis was also employed to evaluate the effect of each estimation indicator on the cost and effectiveness of hypertension screening program. Results and Conclusions: There was 28.3% of the elderly population in Kaohsiung (25,174 of 88,812) who participated in the 1996 EHEP. Among the participants, 14,915 elders participated the EHEP in the following year (1997), with a retention rate of 59.3%. The JNC IV criteria (SBP/DBP> or = 160/95mm Hg or taking antihypertensive drugs) was used, we found that prevalence and incidence rates of hypertension were 24.6% and 6.6%, respectively. Hypertension rates are increasing in the aging process as shown in both prevalence and incidence models. In comparing to non-participants, the prevalence model indicates that each hypertension patient who had attended the EHEP not only saved NT$34,890~34,570 in medical and associated costs, but also increased the life of 128 days. Implications: The present findings suggest that the EHEP is a cost-effective program with health and social welfare policy implications. With the relatively low participation rate of the EHEP, health and social agencies may need more effort in the promotion of free health examination program to attract more potential participants. In doing so, the population at risk for hypertension will be identified for early treatment and the probability of being attacked by stroke could be decreased. Consequently, health care expenditures for treating and caring of stroke patients would be minimized. Finally, clinical practice should call more attention to the significant association of aging and hypertension.