In 2001, Japan launched a national influenza immunisation program for the elderly which provides a subsidy. In order to evaluate the efficiency of the strategy taken in this current program which provides 71% subsidy for all and explore alternative strategies, authors carried out a cost-effectiveness analysis. Authors compared strategies with different levels of subsidy and the use of risk-base targeting by constructing a decision tree model based on the literature. Incremental cost-effectiveness ratios of alternative strategies were estimated deterministically and probabilistically from societal perspective. Probabilistically estimated mean incremental cost-effectiveness ratio of current strategy is US$ 15,535 per YOLS, which can be concluded that current program is cost-effective. Authors also conclude that switching from current strategy to strategy which provides 100% subsidy for all, or strategy which provides 100% subsidy for high-risk elderlies only, can be cost-effective as well.